Old bugs. I believe they have been fixed.

If you are playing as a flametrooper, don't discard or you won't be able to use one of your guns (bug).

In forts, if the enemy team hasn't used the lifts yet, you can do a Regular Jump to get up them! Just run forward and jump, and you'll magically appear at the top. This opens up an unintended secondary exit from the basement. Since this issue appears to go away if the lift is used, you should remember to use the lift at the beginning of each match.