Processor usage doubles after bounce and commit

I have been having an issue since upgrading to OS X 10.11.1 and 12.3 with CPU usage doubling after an offline bounce (WAV or MP3) and after track commit (audio or instrument). I have trashed Prefs using the PT Prefs tool from the site, repaired permissions (Onyx), tried a fresh session with minimal tracks and had the same out come. Everything works great until right at the end of commit or bounce, there is a slight pause at the end of rendering (about a second or two) then the CPU usage nearly doubles and stays there. This doesn't make it hang,
as I've tried to continue playing after the spike. Only resolution is to quit the session and restart.

Has any one else seen this or have any ideas of what to check next?

See screen shots of before and after.

Attached Thumbnails

   

Processor usage doubles after bounce and commit