Someone else and myself are having a similar issue. Mine was a cycle, and I was able to workaround it. Synchronise Alembic & Metahuman animation. (UE5.3.2) - #5 by rigatoni_rampage
I am a little superstitious that it’s something to do with 30fps. I did this a year ago at 24fps and don’t remember this issue. Next time I will repeat the process at 24fps instead and see if that makes things better.