Do you mind getting us a simple set up of your file so we can take a further look? Would be most helpful if you can also provide information of display resolution and system display scaling. We did released a fix for the original issue a while ago and I can no longer repro with the repro file above.
It’s still a persistent issue when creating GUIs directly in Roblox Studio. The 1-pixel gap between UIStroke and a Frame with UICorner is still there, and it can be quite annoying once noticed, especially when trying to make clean rounded UI. I can even include the gui file if you wish.