Bans don't travel to Matrix
Banning a user on gitter.im via
/ban @user:matrix.whatever doesn't also ban them on the bridged matrix room.
The banning user is admin on both the gitter and matrix side (as in the virtual
@something-HASHSOUP:gitter.im user was made admin in matrix).
The way I read this that means #2629 (closed) doesn't work.
I'd be happy to provide more information including the room and users and matrix abuse report number if required.