I just tried it here and Look At seems to be working as expected. Also not seeing any jittering...
Can you submit a bug so we can get system/setup info:
Main Menu > PlayMaker > Tools > Submit Bug Report
If there's a particular project where you're seeing crashes and jittering, and you can share it, please reply to the bug report confirmation email and attach the project (or a download/dropbox link).
Sometimes Unity gets jittery, but restarting usually fixes it. Or it's a background operation going on in windows (backup, virus checking...)