Leg weight error / Calisthenics Tool testing error

I haven’t come across this before and have no idea why it is happening. When testing with the Calisthenics Tool my mesh is all twisted… not seen this in other rig. I have just 3 vertex group and the bones are at 0 roll. No way this should be twisting like this. I assume it will be twisting like this in engine as well… cant get my head around this one.