buttons non working due CSS on MacOS (v5.15.0 only)

Minimal code reproducing the bug: minimal_code_bug_reproduction.py

(Works on Linux, Windows, but not MacOS using PySide2 v5.15.0)

Edit:

Final result of more detailed tests. ANY single of these CSS elements are toxic for QPushButton rendering it unclickable / non-working:

QPushButton {border-radius: 0px;}

QPushButton {background-color: #EBEBEB;}

QPushButton {border: 1px solid #DEDEDE;}

QPushButton is non-working even if it inherits such CSS settings. I.e.: This is also toxic to QPushButton:

QWidget {background-color: #F5F5F5;}