Battleground troop selection.
More than once troops I have not selected have been sent to the b/gs. It is always Legendary troops and they always go to the opposite b/g to which they are. Perhaps a notification could be put when Legendaries are selected for b/gs, odd that the usual "your legendary would work better with" notification never comes up. I will take on the chin what I have lost up till now but now you are aware of this issue would not like to see this happen again. Expect the usual blah, blah that I should watch what I am sending. No it should only send what you select not randomly choose troops that are expensive to buy and hard to get.