If you 'run from/forfeight/endbattle' while in the gym match and then try and re-challenge the gym; it will tell the gym leader that there is already a gym battle in progress for the player (even though there is not)

just another note: its not just the same person trying to rechallenge even if a new person trys to challenge that gym leader it will tell the gym leader a battle is in progress also, thus breaking the gym.

The second bug i've found is that a player can challenge the gyms with a full party of fainted pokemon and the battle will initiate but every move will fail and the battle wont end without a forfeit and cause the above issue too. Logging out will also cause the above issue

The third bug i've found deals with /badges give/take it throws an error in the chat but im unable to determine what the error actually is