Car: Suzuki Swift 1.2L AT 2015
Problem:
Unable to press the shifter button to change gear, unless AC is OFF

Brief history:

issue started after non casa body repair was done (rear collision)
apparently, the shop was not able to seal the 3rd brake light properly, hence shorting occured.
after replacing the fuse, shifter worked fine for a day. but since it the replacements were popping as soon as it was installed (next day), i decided on installing a higher rated fuse temporarily (10A to 20A)*i know, wrong move*; just up until the next day where i have a time to have it fixed.

after electrician (non-casa) replaced the brake switch, and rewired the 3rd brake light (grounded due to water intrusion);
brake switch is OK (but was still replaced)
everything works normally, except that i have to make sure AC is OFF; if AC is ON, there's no way for me to shift from PARK (button is hard to press).
NOW even if the AC is OFF, unless i UNLOCK the Shift LOCK; there is no way for me to move it from PARK

I still have the original, working brake switch; should i return it?
car is with my other boss, and downtime (leaving in casa for diagnostic, is not an optio)
no CEL btw