For some reason, setting a UI to be invisible, changing the resolution, then setting it visible breaks scaling in all the children, but once you edit any of the children it fixes itself. This is affecting UI in the Roblox Player as well, not just studio.
Here’s a gif example: https://gyazo.com/9816bdb434bb1899e537f81bea2e8f53
even setting a child to be invisible and visible fixes it, but I don’t really want to do that in game.
I’m 90% sure this is a Roblox bug, but I can’t post in bug report categories and I don’t want to wait for it to be approved.