Additional Setting not passing for Flamingo due to other plugin

I am using a plugin, “Contact Form 7 – PayPal Add-on Pro” (https://wpplugin.org/downloads/contact-form-7-paypal-add-on/) and whenever the checkbox for “Use Paypal on this form” is checked, the “flamingo_subject: “blah blah blah” setting under “Addtional Settings” does not seem to be passing through to Flamingo. It simply displays [your-subject]

I have tried disabling all other plugins, along with the default theme, and the results remain the same. I have tried both “redirect methods” offered through the PayPal plugin, and method 1 does not pass along the setting, method 2 doesnt seem to support simplecaptcha.

I am attempting to work with the support for the plugin – but nothing has been solved yet, and I’m in a bit of a time crunch.

Since the contact form in question does not have a ‘subject’ line to it at all, is there some way to have a ‘hidden subject line’ or something that I set what it is in the form design, that is never visible to the end-user or anything?