Have a strange issue with the neck and body connection with metahuman character

The different LODs seem to have different levels of “detachment”, as you can see:

Now, in-game they actually do seem to connect right, to a degree:

I should add that this project was migrated from a copy of 4.26 to 5.0.

And here is my character component structure that I copied over from the created metahuman blueprint, to my own character blueprint.

and finally, I think this error that’s popping up might be caused by this neck/body issue

if anyone sees anything jumping out, please let me know. I’m probably going to try recreating the blueprint from scratch here and copying everything over from the metahuman blueprint again in 5.0

(these were previously working fine 4.26)