Updating to 5.1.1 (from 5.0.3) RigMVController soft crash at startup

Some IK Rigs (I guess) are not happy with 5.1.1, we have a bunch of them so it’s hard to know which one is it!

RigMVController.cpp line 16954

if (PinTypes.Num() > ReducedTypes.Num())
{
ensureMsgf(!ReducedTypes.IsEmpty(), TEXT(“Found incompatible preferred types”));
}

Anyone having similar problem?

Dado.