Read the first post, there's a quick fix / hack for that, it is glscene bug, one day i will make a proper fix and submit it to them.

edit: i suspect one of these routines to be faulty: RotateVector, UnrotateVector, dgRollMatrix. these are translated from newton SDK's vector class headers. each function has in code several implementations that i tried, but i didn't have much luck making proper ones, so that would be a good start to start searching for the bug.