Server side error all but one form branch (feedback 500 error)

This seems to have been happening since May 31st or June 1st, when I updated cf7-conditional-fields to version 2.1.5 and WordPress to 6.0.

The error happens here: sweeperland.com/debug-form
For the question: “Which of our products or services are you contacting us about?”, the form only submits if you choose “Equipment Rentals”. For all other choices, you get the 500 error in the console log.

I’ve tried on the default theme.
I’ve tried turning off [most] plugins.
No errors are logged in the debug php error log file.
Caching has been cleared and turned off on every test.

I notice that one field is missing from the list of fields on the failed submission, but is there on the successful submission. That field is “rental-category” (a radio field).

What am I doing wrong here? (Sorry the form is so stupid long and complex.)

More error details:

index.js?nocache:1 POST https://www.sweeperland.com/wp-json/contact-form-7/v1/contact-forms/17126/feedback 500
index.js?nocache:1 Response?{type: 'basic', url: 'https://www.sweeperland.com/wp-json/contact-form-7/v1/contact-forms/17126/feedback', redirected: false, status: 500, ok: false,?…}
index.js?nocache:1 Fetch failed loading: POST "https://www.sweeperland.com/wp-json/contact-form-7/v1/contact-forms/17126/feedback".

Request body:

_wpcf7: 17126
_wpcf7_version: 5.6.2
_wpcf7_locale: en_US
_wpcf7_unit_tag: wpcf7-f17126-p30731-o1
_wpcf7_container_post: 30731
_wpcf7_posted_data_hash: 
_wpcf7cf_hidden_group_fields: ["other-referral","parts-help-button","parts-help-button","same-billing-address[]","company_name-billing","name-billing","address-billing","po_number","city-billing","state-billing","zip-billing","make-part-order","model-part-order","serial_number-order","qty","part_number","description","qty_2","part_number_2","description_2","qty_3","part_number_3","description_3","qty_4","part_number_4","description_4","qty_5","part_number_5","description_5","make-parts","model-parts","serial_number-parts","pic","comments-parts","same-billing-address[]","company_name-billing","name-billing","address-billing","po_number","city-billing","state-billing","zip-billing","make-part-order","model-part-order","serial_number-order","qty","part_number","description","qty_2","part_number_2","description_2","qty_3","part_number_3","description_3","qty_4","part_number_4","description_4","qty_5","part_number_5","description_5","make-parts","model-parts","serial_number-parts","pic","rental-category","rental-category","rental-category","rental-category","rental-category","rental-category","rental-category","rental-category","Model-rental","date-sweeper-rental","sweeper-rental-period-num","sweeper-rental-period-dmy","special_considerations-sweeper","more_info-sweeper-rental[]","more_info-sweeper-rental[]","date-pwx-rental","pwx-rental-period-num","pwx-rental-period-dmy","special_considerations-pwx","more_info-pwx-rental[]","more_info-pwx-rental[]","scrub-type[]","scrub-type[]","intended-use-rental","if-other1","application-location","floor-type-rental","otherspecify","EstimatedSquareFootage","file-723","rental-period-num","rental-period-dmy","rental-instructions","date-sweeper-rental","sweeper-rental-period-num","sweeper-rental-period-dmy","special_considerations-sweeper","more_info-sweeper-rental[]","more_info-sweeper-rental[]","date-pwx-rental","pwx-rental-period-num","pwx-rental-period-dmy","special_considerations-pwx","more_info-pwx-rental[]","more_info-pwx-rental[]","scrub-type[]","scrub-type[]","intended-use-rental","if-other1","application-location","floor-type-rental","otherspecify","EstimatedSquareFootage","file-723","rental-period-num","rental-period-dmy","rental-instructions","scrub-type[]","scrub-type[]","service_address","service_address","serv-address","serv-city","serv-state","serv-zip","unit_type","make","model","serial","last-service","service_needed[]","service_needed[]","service_needed[]","comments-service","service-attach1-1","service-attach1-2","service-attach1-3","additional_units","additional_units","unit_type2","make2","model2","serial2","last-service2","service_needed2[]","service_needed2[]","service_needed2[]","comments-service2","service-attach2-1","service-attach2-2","service-attach2-3","serv-address","serv-city","serv-state","serv-zip","unit_type2","make2","model2","serial2","last-service2","service_needed2[]","service_needed2[]","service_needed2[]","comments-service2","service-attach2-1","service-attach2-2","service-attach2-3","cb-interests2[]","comments-general"]
_wpcf7cf_hidden_groups: ["specify-other-group","Parts-Group","Parts-Order","Parts-Help","Rental-Group","Sweeper-Rental","JetVac-Rentals","Other-Rentals","Scrubber-Rentals","Service-Group","diff-serv-addrss","Service-Another","Supplies-And-Info","Wants-Quote","Wants-Demo","Supply-Info-Request","General-Info"]
_wpcf7cf_visible_groups: ["Equipment-Sales","buy-or-rent","Wants-Purchase"]
_wpcf7cf_repeaters: []
_wpcf7cf_steps: {}
_wpcf7cf_options: {"form_id":17126,"conditions":[{"then_field":"JetVac-Rentals","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Sewer Vac Truck \/ Jetter"}]},{"then_field":"JetVac-Rentals","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Hydro Excavator"}]},{"then_field":"Scrubber-Rentals","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Walk-Behind Scrubber (Wet Cleaning)"}]},{"then_field":"Scrubber-Rentals","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Rider Battery Scrubber (Wet Cleaning)"}]},{"then_field":"Scrubber-Rentals","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Rider Propane Scrubber (Wet Cleaning)"}]},{"then_field":"Other-Rentals","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Walk-Behind Scrubber (Wet Cleaning)"}]},{"then_field":"Other-Rentals","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Rider Battery Scrubber (Wet Cleaning)"}]},{"then_field":"Other-Rentals","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Rider Propane Scrubber (Wet Cleaning)"}]},{"then_field":"Other-Rentals","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Walk-Behind Sweeper (Dry Cleaning)"}]},{"then_field":"Other-Rentals","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Rider Propane Sweeper (Dry Cleaning)"}]},{"then_field":"Sweeper-Rental","and_rules":[{"if_field":"rental-category","operator":"equals","if_value":"Street Sweeper"}]},{"then_field":"specify-other-group","and_rules":[{"if_field":"user-source","operator":"equals","if_value":"Other"}]},{"then_field":"Parts-Order","and_rules":[{"if_field":"parts-help-button","operator":"equals","if_value":"Yes"}]},{"then_field":"Parts-Help","and_rules":[{"if_field":"parts-help-button","operator":"equals","if_value":"No"}]},{"then_field":"Supply-Info-Request","and_rules":[{"if_field":"service-choice","operator":"equals","if_value":"Cleaning & Janitorial Supplies"}]},{"then_field":"Wants-Demo","and_rules":[{"if_field":"demo-quote-request","operator":"equals","if_value":"I'd like to schedule a demo"}]},{"then_field":"Wants-Quote","and_rules":[{"if_field":"demo-quote-request","operator":"equals","if_value":"I'd like to request a quote"}]},{"then_field":"Wants-Purchase","and_rules":[{"if_field":"intent","operator":"equals","if_value":"Buy"}]},{"then_field":"Rental-Group","and_rules":[{"if_field":"service-choice","operator":"equals","if_value":"Equipment Rentals"}]},{"then_field":"General-Info","and_rules":[{"if_field":"service-choice","operator":"equals","if_value":"Other"}]},{"then_field":"Supplies-And-Info","and_rules":[{"if_field":"service-choice","operator":"equals","if_value":"Other"}]},{"then_field":"Supplies-And-Info","and_rules":[{"if_field":"service-choice","operator":"equals","if_value":"Cleaning & Janitorial Supplies"}]},{"then_field":"Service-Another","and_rules":[{"if_field":"additional_units","operator":"equals","if_value":"Yes"}]},{"then_field":"diff-serv-addrss","and_rules":[{"if_field":"service_address","operator":"equals","if_value":"Yes"}]},{"then_field":"Service-Group","and_rules":[{"if_field":"service-choice","operator":"equals","if_value":"Repair Services"}]},{"then_field":"Parts-Group","and_rules":[{"if_field":"service-choice","operator":"equals","if_value":"Equipment Parts"}]},{"then_field":"buy-or-rent","and_rules":[{"if_field":"intent","operator":"equals","if_value":"Buy"}]},{"then_field":"buy-or-rent","and_rules":[{"if_field":"intent","operator":"equals","if_value":"Rent"}]},{"then_field":"Equipment-Sales","and_rules":[{"if_field":"service-choice","operator":"equals","if_value":"Equipment Sales & Leasing"}]}],"settings":{"animation":"yes","animation_intime":"200","animation_outtime":"200","conditions_ui":"normal","notice_dismissed":""}}
_wpcf7_recaptcha_response: 
contact_name: Ryan
company_name: b
phone: 7171234567
ext: 
zip: 21231
contact-time: 
contact-method: 
pros-email: [email protected]
email-539: [email protected]
user-source: Current Customer
other-referral: 
service-choice: Equipment Sales & Leasing
textarea: 1518566199.1643999084
product-int: 
machine-class: Floor Scrubbers
intent: Buy
about-application: 
application-attachment: (binary)
buy_state: 
buy_zip: 
product_state: 
product_zip: 
comments-sales: test
company_name-billing: 
name-billing: 
address-billing: 
po_number: 
city-billing: 
state-billing: 
zip-billing: 
make-part-order: Select Make...
model-part-order: 
serial_number-order: 
qty: 
part_number: 
description: 
qty_2: 
part_number_2: 
description_2: 
qty_3: 
part_number_3: 
description_3: 
qty_4: 
part_number_4: 
description_4: 
qty_5: 
part_number_5: 
description_5: 
make-parts: Select Make...
model-parts: 
serial_number-parts: 
pic: (binary)
comments-parts: 
Model-rental: 
date-sweeper-rental: 
sweeper-rental-period-num: 0
sweeper-rental-period-dmy: Days
special_considerations-sweeper: 
date-pwx-rental: 
pwx-rental-period-num: 0
pwx-rental-period-dmy: Days
special_considerations-pwx: 
intended-use-rental: -Select-
if-other1: 
application-location: 
floor-type-rental: -Select-
otherspecify: 
EstimatedSquareFootage: 
file-723: (binary)
rental-period-num: 0
rental-period-dmy: Days
rental-instructions: 
service_address: No
serv-address: 
serv-city: 
serv-state: 
serv-zip: 
unit_type: Select...
make: 
model: 
serial: 
last-service: Within 6 Months
comments-service: 
service-attach1-1: (binary)
service-attach1-2: (binary)
service-attach1-3: (binary)
additional_units: No
unit_type2: Select...
make2: 
model2: 
serial2: 
last-service2: Within 6 Months
comments-service2: 
service-attach2-1: (binary)
service-attach2-2: (binary)
service-attach2-3: (binary)
comments-general: 
campaign: 
g-recaptcha-response: 03ANYolqv3Q (..etc)