I don’t know if this is a bug, so I’m just gonna post here for now.
So when my friend unions something (a window) it becomes transparent for me but not for him. When I union the window it becomes transparent for him but not for me.
Maybe when he unions that thing, he pressed wrong button, like he must make it negative first and then union with the part that is unioned or non-unioned. Sorry if you don’t understand me, I barely even understanded my self, I’m typing this at 1 AM.
I had sth similar last week, i made unions and saved the game to roblox, i saw the output to confirm it was published, everything was fine, so i exit studio. Hours later, i opened studio and my unions dissapeared! so i tried separating the unions, but, when i tried, they dissapeared from the workspace and from my explorer. I tried with Ctrl+Z but they werent there; I think it should be a roblox studio bug.
This is a local error, if you play the game outside of studio it will be there normally, this is probably due to your friend’s studio (or yours) and is visible on their screen, do not worry about this as every other player will be able to see it, this is just a client side bug, very normal.