This is a bug where meshes upon uploading do not show up much like a corrupted union. When uploading the Mesh, at fist it is not visible but still retains shadows and collision data. Normally when uploading a mesh it loads on the first try. This is by adding it from the properties bar and loading it from file directly into the game.
This bug happens almost every time and is fixed by re-uploading it with the settings prompted you chose previously. To reproduce, select a file in game when adding the mesh. Select your settings that are prompted and the mesh appears with no visuals. Upload again exactly as you did before and it loads. This creates 2 instances in your inventory of the exact mesh but only 1 of them show the first time you upload it.
The bug happens in studio. Here is a place I tested it out on. Upon closing and re-opening the game, the meshes were fixed. However this is inconvenient when you need to place it right away.
I’ve encountered this bug weeks if not months ago. This has been a problem for awhile but since I’m uploading over 400 mesh parts this week it’s become a real hassle. Hopefully this gets fixed.