This happened to my colleague, but I was the classroom next door.
My colleague was showing Clash of the Titans at the end of the year after a unit on Ancient Greece. There is mild nudity at the beginning and the end of the movie, but they were in the middle of the movie so there shouldn’t have been an issue.
He left the video paused at the right spot (we still had VCRs like 10 years ago when this happened), but the sub somehow managed to show both the nudity at the beginning and the end of the movie. The nudity scenes were hours apart and the class was only 40 minutes.
Then, the sub wrote an email to the principal about how my colleague made him show nudity.