I do not know where how/where the change to "with time zone" occurred. Maybe in the upgrade from postresql 9.3 to 12. Qt4 to Qt5?
No idea. Both of those are major version updates so it could have been in either one. The Qt development and deployment architectures changed quite a lot going from 4 to 5.

Glad you were able to resolve the problem. Sorry I could be of more help.