Eh, no. I queue flex in QP. I get games within a minute, usually within 30 seconds. I also leave a lot of games instantly as I only play payload/hybrid. I also leave games against widow. In 3 hours I would have queued maybe 40-50 games I would guess. I have queued for 100s of games on those accounts and never had backfill. It is statistically significant and more so when comparing to my main account which I actually play less on these days and still get a lot more backfill.