Wierd game plz help explain

The way this game was set up I felt i was in a custom game accidentally... like i was the only one not in on the joke or something.

MF was supposed to be my support but at the start of the game she asked if i was ok at bot by myself, i said yea and didnt really ask why but she was gonna duo lane top with mao

it was set up as rengo and j4 jungle teemo vs vieg mid jinx bruam vs mf mao top and ashe vs cait (me)

is this a common strategy or something??? [zombie-brand-mindblown]