I think uvac.fr has a problem with payments currently. I have a gap of payouts between 19:30 UTC and 21:50 UTC. I saw the pending balance getting bigger and bigger but it suddenly vanished without going into a payment. Then new payments continued again at 21:50 UTC but the accumulated pending amount from the previous 2+ hours wasn't included.
Im not expert but for previous replies I think that probably the mixin at 5 delays the payament and when it send the payament the tx is so big to get stuck in mempool