This is not going to be the most helpful post, since there is no repro, but I figured I should post it somewhere to see if I am not the only one.
Occasionally when I am messing around in studio certain objects just disappear. This usually happens when working with UI. And its strange because it doesn’t disappear from the explorer (at first). First in manifests in it not existing in play solo. All of a sudden a script errors for a frame not being their yet the explorer says it should be there. I publish, close out of studio, and re-open. And all of a sudden the frame(s) aren’t there.
The frames (this time) were in a folder in a ScreenGui; Idk if that matters but that’s one factor.
Just going to throw it out there.