[Client] [ARAM] Empty champ selection window. Happened twice in a week.

In client, after selecting an ARAM game, after clicking the "I'm ready" button, while entering the champion selection screen.

The champion selection window remains empty. I can see the window title, the maximize and close button in upper right corner of window. But the content is just not there.

Happened twice in a week. I would say 2 times for 15 games.

Important thing to notice, both time, when happened I heared the sound of the exchange proposition, the "Tching" (sword clinking sound). I believe the bug possibly appears when someone ask for a champion exchange with me before/at same time my UI is initializing. This is probably creating a conflict at initialization time.

No work around found. I had to close the client. Got a time malus of 15 miuntes each time.

This is obviously an annoying and frustrating bug for us, as this cause a short ban.