Metahumans breaking on import is it the recent updates?

it looks like new bones were added to the updated metahuman? so the old maya files i’ve rigged is now going to break with newer metahumans? or am i wrong?

this popped up when i closed out of that ue project.
error

update: I just tested it on a new exported MH and it works…so whatever was in that older MH folder i copied over is what fixed it. i still don’t know what tho, which is frustrating.