Coupon Add-On and PayPal Commerce Platform Add-On not compatible?

So apparently, the GF Coupon Add-On and the PPCP Add-On cannot be used together? Has anyone else run into this? GF tells me the fix is in their backlog. How can a payment solution not be able to accept a coupon???

Upon second attempt of using a coupon at PayPal Checkout, users are reporting that the link tries to connect to PayPal, but then closes and just goes back to the order form.

See video here: https://drive.google.com/file/d/13QAOWxVLzepsI2EpuFN-AiaUi3Crvrp_/view?usp=drivesdk

Functions.php: http://snippi.com/s/vr1ga3y

Note - I had to disable the coupon field due to this issue, so I do not have a functioning form showing the issue, I can set up a form to show the issue if needed.

Any help, workarounds or advice is welcome.

Thanks, Sheri