I’ve been confused by the “share” window where the screen dimensions cut content off perfectly, and there is no scroll indicator, so you don’t realize there’s more to the UI.
GDPR "consent" popups are sometimes not usable on the first gen SE, because some of them position: absolute with a fixed size that's larger than the screen. Coincidentally, the "Accept all" button is always reachable, with the "Settings" or "Deny most" button conveniently located below the unreachable fold.
Or Facebook photo preview where it cuts off the bottom until you open it to full, and no indicator it’s cut off except your own experience with crappy cutoffs. That often changes the meaning of pictures/memes.
