FBoneContainer::MakeMeshPoseIndex crash (out-of-bounds array)

This is somewhat complex to reproduce. We've narrowed it down to MotionMatching / BlendStack nodes (see stack attached regarding that.)

The crash occurs because the actor's skeleton is being LODed from 0 to 3 but some of the attributes on the blended sequences contained are referencing LODed bones (which will evaluate to invalid bones.) This is what led to the crash. We think it's because of how MotionMatching works (via pose history) which leads to Integer Attributes which reference now-LODed bones to be blended, but we haven't completely narrowed it down yet nor confirmed that. There's a suggested fix for this crash below.

The crash occurs in FBoneContainer from this method (out-of-bounds array)
FMeshPoseBoneIndex MakeMeshPoseIndex(const FCompactPoseBoneIndex& BoneIndex) const
{
return FMeshPoseBoneIndex(GetBoneIndicesArray()[BoneIndex.GetInt()]);
}