Sometimes when i turn my car off (991.2 TTS) the windshield wipers jump. Has anyone else experienced this?

 

I just passed 5,000 miles in and have not had this occur, I’d get it checked out.

 

It's normal and does it to extend the life of the blades. IIRC it helps the blades from taking set (keeps the blades flexible). My 2015TTS does it and so did my 2012 991S. I'm betting they all do it and you just haven't noticed it.

 

Have had the dance on several PCars. Just a small shutter and settles back in. Might happen more i believe if wipers are set to auto.

 

Yes, happens all the time when I have the wipers in Auto/sensor rain delay mode.
As mentioned above, it is designed to extend the life of the blade itself, or so says my dealer rep.
It's normal. Let that be the least of the issues you have with that amazing car of yours.