Issue with skinned mesh importing

I’m trying to import a blender rig to roblox studio, i made it myself and did a lot of the weight painting, the entire rig works perfectly fine EXCEPT for the back of the head

the back of the head decides it’s gonna lose all of its weight painting but everything else is perfectly fine.

I’ve tried looking for youtube solutions and help in the hidden devs server, but nothing i’ve found has worked. I need this for a game i’m working on.