Thanks for reporting this to us, this is an issue that we are aware of.
But being aware isn't enough, this has been going on for months and still is. Not sure when it started exactly, but it's close to 4 months.
Just last week I was grouped with a friend and we couldn't do ANY because it was resetting our roles every 30 sec or so. We decided to just go do something else on our own
And at another time this bugged up feature grouped us into a 2 tank and 2 healer party. Like it isn't hard enough to talk some sense into most of the current damage roles, we now have to tell tanks and healers to do damage.
This bug may show a lot of group finder matches, but does it also show the rejected ones? Queue times are much longer because this junk isn't being fixed, it creates a volatile community. You should work on making people want to stay, not leave in frustration!