FWIW, I have the same thing on a Mk2a with a single drive. I also have a Mk2 that hasn't yet shown the problem.

I am running 2.0-b11 with an older hijack (~200) on that box. It tends to happen up after about 50 minutes. Tends to happen on the same stretch of road. (Even when the GPS is not connected :-) Seen it three times so far.

Cheers,

Rex.