Avatar armature won't effect mesh only in unity

Recently, while setting up any avatar in unity and I get to what I have to do in the rig tab for my model, I notice that the armature moves, but not the mesh. It is perfect in blender and everything is set up exactly how it was for every other avatar I have made. I can not find a way to fix this. The weight painting and parenting is perfect in blender and the assigned bones in unity are perfect.
Just to iterate, these two models are posable in blender, but not in unity.
This has plagued me for a few months and I can’t find any information on this online.

I recently, finally, managed to get this to work. It turns out I have to parent the armature and mesh manually from the perspective view using the right click context menu, so then they are parented as an object. It usually takes a few attempts so it randomly gets set as an object parent instead of the normal armature parent. The only other way I can get an armature to work is to set it as an armature parent with empty groups if I haven’t weight painted it or made vertex groups yet. I could not find anything about this issue online the entire time I’ve been trying to find a way around this.