A while back I had a crash that seemed to desync my ability to cancel a mission - it no longer refreshed after the daily rating.
I stopped playing for a few days this week - I was getting tired of 'pregnant' 'assign to right room' and 'dancing' missions (all which are terrible missions btw)
I logged back in about 36 hours ago, and haven't been able to cancel ANY daily missions. Both vaults have completed their daily rating - and I am still unable to removed any missions. - I don't have an 'X' option.