Not sure this is the right place to do this, but here are the reproduction steps:
- Open up ShooterGame.
- Find “Rifle”, the mesh.
- Right click its asset and click Export. Proceed with the export.
- Import the mesh in 3D Studio max 2010, and export it again as a FBX.
- Right click the asset again and click Reimport.
- Select your 3D Studio Max exported mesh.
At least on my end, the asset starts to flicker a little bit, and if you double click it… you’ll get thrown into the root of your content folder and if you try to go back, the Mesh has now vanished from the Content Browser. If you now try to import it again, it says it already exists - but you still can’t see it.