In Aaliance chat is a notice about an alliance attack. I click on it and want to join.
In THIS screen there is no info about the timings which is normaly available when going into the alliance war screen.
So I did not know the alliance member was far away when I joined the attack.

As soon as I joined the attack I got a message my troops had returned to my city, but I also got a message the 20 points stamina had been subtracted. When I went to the normal alliance war screen I could see he was over a hour away on a 5 minute attack.
The game should NOT have accepted my joining the attack and should not have subtracted the stamina points.