It’s just Studio being buggy unfortunately. However they’re going about underlining supposed non-existing modules seems to be really unreliable currently.
Got this issue yesterday.
All of my scripts requiring a certain module (Roact), just gave an error. Wasted an hour on the issue and after restarting studio a couple times the issue suddenly disappeared.
I have no clue what I did to fix it, but I’m glad the issue is gone.