Audio dropout related to heavy editing?

I’ve had the same issue on a couple songs… Running Mixbus on a 2.16 Intel Core 2 Duo Macbook, 2 gig of ram. Here’s the thing: When I make lots of edits (as in, 3 or 4 per measure), the audio of one edit region will drop out during playback. It seems intermittent, and occurs on different edit regions at different times. Certainly could be user error, I’m just not sure how.
Any ideas (before I submit it to the code-heads?

Submit it. It is a known issue, or rather semi-known. I say this because I have occasionally heard reports of it, but due to the intermittent nature of it I don’t think an exact cause has been found. Every bit of info helps in this though, so the more detail you can give the better.