Ok, so with a bit more investigation the problem can be fixed by unhiding the leg_L0_0_jnt. This has a scripted op undeneath it setting a number of things related to the leg bend, and I can only guess that the op is not being evaluated on certain frames, causing the twisting.
My fix for now is to make it visible yet unselectable, and shrink the shadow scale down so its not confusing to animators. This is using gear 1.1.0, will test gear mc tomorrow and if it repros, maybe dig out miquel's email for a bug report ;) -- www.matinai.com
