Capturing teammate cap bug

We were playing a 3v3 with Brandreas, Usernames captured his cap and in the second turn I sent Kiev(Brandreas's cap) 5 infantry with air transport. Air transport couldn't reach Kiev so I unloaded them in half way and attacked Kiev. Brandreas sent 5 bombers to, we killed all of Usernames units but Usernames made a wall near Kiev and the game didn't let me capture Kiev.



Is it a bug or it supposed to happen?

Yup, it did happen. Was weird to us both.

Anyone knows what happened?

It's just one of usernames glitch .

Not a bug. Brandreas got the city, but since he couldn't capture it, both Roncho and Brandreas remained outside. In the same turn Usernames created a wall around the city and you found yourself outside of it.