Hello, i also had this same issue bounced back and forth between proseries and quickbooks support.  I was able to fix it on my end.  What i did was:

1. uninstall proseries 2020 from the workstation

2. Manually delete C:\ProWin20

3. Reinstall proseries 2020 (for me it was workstation install from network folder)

4. Update proseries 2020

5, Initiate export from quickbooks 2019

Success!