I recently made a flowlayout in pyqt, and I this also happens with a combobox, where there are flashing visual glitches when hovering items in a QMenu or QComboBox, you can also see it when I add a widget to the flow layout.
Here is code to flowlayout: https://paste.pythondiscord.com/JL4A
Here is code to the flow layout logic: https://paste.pythondiscord.com/W42A
I tried to disable updating before and after adding the tag, but it did not seem to chnage anything
self.flow_layout.parentWidget().setUpdatesEnabled(False)