after save in ‘quick edit’ mode, the shipping class value will gone

HI~

wordpress 5.4.1
woocommerce 4.1.0
theme: Twenty Twenty

When I use ‘quick edit’ mode and save, the the shipping class value will gone.
But when using ‘edit mode’, it is normal.

Thumbnail
1. https://screencast.com/t/zWo1hpcg
2. https://drive.google.com/file/d/17nutean5RQdj-9mbj_6HCaw6PI6ygL5o/view?usp=sharing

### WordPress Environment ###

WordPress address (URL): https://test03-shop-flatsome.pro1.designworks.tw/testweb
Site address (URL): https://test03-shop-flatsome.pro1.designworks.tw/testweb
WC Version: 4.1.0
REST API Version: ? 1.0.7
WC Blocks Version: ? 2.5.16
Action Scheduler Version: ? 3.1.5
WC Admin Version: ? 1.1.1
Log Directory Writable: ?
WP Version: 5.4.1
WP Multisite: –
WP Memory Limit: 512 MB
WP Debug Mode: –
WP Cron: ?
Language: en_US
External object cache: –

### Server Environment ###

Server Info: Apache
PHP Version: 7.2.30
PHP Post Max Size: 32 MB
PHP Time Limit: 30
PHP Max Input Vars: 1000
cURL Version: 7.62.0
OpenSSL/1.0.2k

SUHOSIN Installed: –
MySQL Version: 5.6.47-cll-lve
Max Upload Size: 32 MB
Default Timezone is UTC: ?
fsockopen/cURL: ?
SoapClient: ?
DOMDocument: ?
GZip: ?
Multibyte String: ?
Remote Post: ?
Remote Get: ?

### Database ###

WC Database Version: 4.1.0
WC Database Prefix: wp_
Total Database Size: 0.82MB
Database Data Size: 0.66MB
Database Index Size: 0.16MB
wp_woocommerce_sessions: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_api_keys: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_attribute_taxonomies: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_downloadable_product_permissions: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_order_items: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_order_itemmeta: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_tax_rates: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_tax_rate_locations: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_shipping_zones: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_shipping_zone_locations: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_shipping_zone_methods: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_payment_tokens: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_payment_tokenmeta: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_woocommerce_log: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_actionscheduler_actions: Data: 0.00MB + Index: 0.02MB + Engine MyISAM
wp_actionscheduler_claims: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_actionscheduler_groups: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_actionscheduler_logs: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_commentmeta: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_comments: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_links: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_options: Data: 0.65MB + Index: 0.04MB + Engine MyISAM
wp_postmeta: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_posts: Data: 0.01MB + Index: 0.01MB + Engine MyISAM
wp_termmeta: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_terms: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_term_relationships: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_term_taxonomy: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_usermeta: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_users: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_wc_admin_notes: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_wc_admin_note_actions: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_wc_category_lookup: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_wc_customer_lookup: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_wc_download_log: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_wc_order_coupon_lookup: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_wc_order_product_lookup: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_wc_order_stats: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_wc_order_tax_lookup: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_wc_product_meta_lookup: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_wc_tax_rate_classes: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_wc_webhooks: Data: 0.00MB + Index: 0.00MB + Engine MyISAM

### Post Type Counts ###

attachment: 1
page: 6
post: 2
product: 1

### Security ###

Secure connection (HTTPS): ?
					Your store is not using HTTPS. Learn more about HTTPS and SSL Certificates.
Hide errors from visitors: ?

### Active Plugins (1) ###

WooCommerce: by Automattic – 4.1.0

### Inactive Plugins (3) ###

Akismet Anti-Spam: by Automattic – 4.1.5
Hello Dolly: by Matt Mullenweg – 1.7.2
Limit Login Attempts Reloaded: by WPChef – 2.12.2

### Settings ###

API Enabled: –
Force SSL: –
Currency: USD ($)
Currency Position: left
Thousand Separator: ,
Decimal Separator: .
Number of Decimals: 2
Taxonomies: Product Types: external (external)
grouped (grouped)
simple (simple)
variable (variable)

Taxonomies: Product Visibility: exclude-from-catalog (exclude-from-catalog)
exclude-from-search (exclude-from-search)
featured (featured)
outofstock (outofstock)
rated-1 (rated-1)
rated-2 (rated-2)
rated-3 (rated-3)
rated-4 (rated-4)
rated-5 (rated-5)

Connected to WooCommerce.com: –

### WC Pages ###

Shop base: #6 - /shop/
Cart: #7 - /cart/
Checkout: #8 - /checkout/
My account: #9 - /my-account/
Terms and conditions: ? Page not set

### Theme ###

Name: Twenty Twenty
Version: 1.2
Author URL: https://www.ads-software.com/
Child Theme: ? – If you are modifying WooCommerce on a parent theme that you did not build personally we recommend using a child theme. See: How to create a child theme
WooCommerce Support: ?

### Templates ###

Overrides: –

### Action Scheduler ###

Complete: 5
Oldest: 2020-05-12 09:23:07 +0000
Newest: 2020-05-12 10:11:00 +0000