Working with a blender to unreal workflow if that matters (but I suspect it does not).
When I first import an FBX, all is fine, it gives me an import dialog and loads the skeleton, actions, mesh, and materials. When I re-export it, unreal loads the changes to the MESH ONLY (with no dialog accessible). It does not re-import the skeleton, or load any new actions. If I want to get those to load up, I have been forced to delete everything from content (detaching everything), delete the fbx, restart unreal, re-import everything, then re-attach everything. This is a painful process, but I cannot find a means of re-importing this adjacent data. Is there something I am missing?