Weight painting mirror issues in edit mode

I am trying to do weight painting in edit mode, but the vertex groups fail to mirror.

I have checked in edit mode, and I can move vertexes and it successfully mirrors them. The mirror works correctly when using the weight painting tool, but in mirror mode it fails. X-Mirror is on. All the vertex groups and bones are named with a .L/.R format, and I have tested the bones and they can mirror as well.

I have also attempted to manually mirror using “Copy vertex group” and “Mirror vertex group”, but it either says that all the vertexes failed to mirror, or it’ll only mirror the vertexes at the very center of the model.

I’ve searched on Stack Exchange and a few other forums and I’ve been unable to find a post that can help me, as most of them are about the mesh not being symmetrical (and all other X-Mirrors work on this model) or the groups not being named correctly (but I’ve double checked and they are named correctly), but if this is a duplicate I apologize