mediabay not playing all loops

I seem to have encountered yet another problem in media bay. When auditioning loops with the track playing, and the loops synched to the tempo of my working track, every second or third loop auditioned will not play any sound. the play bar animates across the waveworm as usual but no sound plays.

This is only happening when i have the track playing, not when i am just going through the loops.

anyone else come across this?

updated to 6.02 and same problem?

no one else has this problem?