Friend invites me, I join and end up in the ranked match screen in a party with him. I start to chat there but he doesn't reply, which is strange.
I wait a bit, he suddenly asks in Steam chat "hey where are you?". I'm like "What do you mean, I'm here in your ranked game party, followed your invitation." And he's like "What? I'm in a custom match."
And sure enough, he was. in BOTH at the same time. O_O