I’ve been flying the FENIX exclusively lately and use PACX every flight.
I’ve never had that issue.
I did a PACX search on FENIX discord and there is nothing related to it either, given you have the issue with both variants of the A320, have you tried uninstalling / re-installing PACX? Or ensuring it is updated?
Does this happen at the same airport (maybe a scenery issue with a bump in the runway). Or are you exceeding gear speed on the ground
I’m just not sure how PACX can cause this is all.