Low priority queue timer cancelling

I am on those pesky 20 minute queues for 5 games and have run into an issue that I had a few months ago the last time I was on this queue. I start the queue and go on to do some web browsing to pass the time and anywhere from 10 to 19 minutes into the queue, it cancels itself. I then have to restart the queue. The only way I seem to be able to get into games is by keeping the League window open on my screen and passing my mouse over it every few minutes. Is there a reason for this or is this a bug?

I have seen this issue on my old pc a few months back. I have reinstalled the program and the issue persists.