Crash on comping and looping on Sonar Platinum (latest)

Looping and comping very buggy.
 
I'm working on a movie and start editing the dialogue.
We started a ADR session (overdub) and recorded 20 takes. Recording was done while looping. The actors where looking on a second screen were the video was running and we looped a scene. There were some crashes but I was thinking the extensive use of Sonar including video preview where causing this.
 
But now I start editing by speed comping. The system keeps on crashing while looping and navigating with the cursor keys. Movie keeps on running but Sonar freezes.
I tried it on two systems with and without SSD. One system is a fairly new one.
 
I think Sonar Platinum (latest) has a comping or looping bug. Has anyone the same experience?