I have this issue that appeared in 5.5.1 and 5.5.2.
I created two minimal projects that are exactly the same (based on third person demo from unreal) with the added code to duplicate the skeletal mesh of the main character in the demo. When I cook the data and run the game in standalone it causes a crash in part of the code that has Nanite::FResources::Serialize in the callstack, inside the DuplicateObject.
The other project has the same structure but is using 5.4.4 - everything works fine, standalone and editor.
If anyone know anything about this, please do tell. My suspicion is that this is due to all the Nanite changes that came with 5.5. Oh and btw, turning nanite on or off on the mesh that is getting duplicated changes nothing.
What are you doing that requires you to duplicate a skeletal mesh in a packaged build? Those are assets and usually those aren’t things that you’d create or want to modify in a shipped game.
Without having the actual callstack it’s really hard to hazard a guess but there are references to target platform and cooking in FResource::Serialize that I would be surprised if they were supported outside of the editor/cooker.