Calling UpdateInstanceTransform on a HISMC with a transform only containing rotation or scale would not update the transform at runtime or cooked.
1.Create an Actor + a HISM component with 1 instance in a map
2.In BP call UpdateInstanceTransform with a transform only containing a rotation or scale, no position
3. Running in PIE, you will see the instance being updated with your transform, where as in a cooked buld or -game you would not.
There's no existing public thread on this issue, so head over toAnswerHub just mention UE-63488 in the post.