Incorrect pitch

I was working on a score, and suddenly, while I was working it, the pitches started to come out wrong, transposed a bit more than a semitone down. Five minutes ago, I posted about this as a comment on an old thread from someone else with the same problem, (https://musescore.org/en/node/348100), but I don't know if comments on old threads get read, so I'm creating a new topic here.

I am attaching my score here.