Possible Dynamic Queue roll select bug: got wrong roll

i queued TOp/Mid and got jungle. Another fella in queue went Support/Top, and got adc

just did same queue again while typing (someone dodged last queue), and i got support this time

edit: if it makes a difference i always queue as support/jungle but wanted to play a different role, my most recent ranked game was queued as support/jungle, perhaps this is why?