As Jessica said, they can carry over from past years of those people didn't accept them then.

Hi !

As mentioned, they might have been left over from last year (i.e. dances that didn't get accepted before Masquerade ended previously, but then were after it started this year).

You can always submit a ticket to have a UA look into it and confirm if it is something you could get in trouble for. :)

Following up. Did this resolve your issue?