I wanted to post an update of something i actually found resolved this crash i posted above. I have imported this LavaFalls.map file many times and it has generated the mesh and uses the auto replace existing mesh in the HammUER settings.
It started crashing on me over time of updating the map meshes would make the import process crash. Once i hit open map in the hammUER window i click the X to reset the meshes directory and let it generate the meshes again in this new directory and now the map is no longer crashing. (no changes made to the source map file)
Hoping this helps figure out what the problem is. Feel free to DM me on discord if you need any more info