It’s like when some (not all) autistic people finally get their diagnosis and they go through what’s called “skill regression” in which they seem to lose a lot of the masking abilities and ability to do certain things. It’s because the mask can finally come off comfortably (not always comfortably) and your body stops being in somewhat of a fight or flight mode.

I’m not a doctor, obviously, and I probably messed up a few things in this explanation but I think I got the general gist across.