You should just try to use MeshParts imo, if you can’t I don’t really know what to say since I don’t mess with unions much, only importing and converting to Meshes
I don’t really want to do this as I have over 100 doors I’d have to convert. Also, it would require me to alter my door teleportation system, which I ideally want to avoid.
I have had this same issue but not to me directly, but a few players experienced it. What I did to help some of them was preload the asset with ContentProvider, but it still ended up happening occasionally. I think this is due to slow loading with their device/internet connection. Usually they can fix it by rejoining the game until it works, because if they don’t, sometimes the object will be invisible and not load no matter how long they wait. Makes me wonder if its something more than just their device/internet messing up the loading of the part. Either way, it seems to only happen for unions so like others have said, converting it to another basepart would be a good idea.