I think that was because they did the special 8th anni missions for those and needed to use the mission clear check for that (smaller dev team could also be the reason)
Haven't seen that myself but in the past have seen some crashes from not being able to claim some mail that has the resource you are trying to use, you end up showing you have it when you do not (the mail resets to not claimed). If you are not trying to get something from mail to do it what EX level are you trying to get?