In one of my previous lives I worked in recruitment and one of our customer airlines was RYR and, with a previous background in Crew Scheduling, I picked up on RYR's situation … at that time.
Flight Crew can operate a maximum of 100 block hours in 28 days and a maximum of 900 block hours in 12 consecutive months, RYR may have a slight amendment to this but it's a maximum of 900 hours per year.
RYR work their pilots pretty much to the limit, I mean if they're going to the Canaries and back (8 hours) they can only work 12.5 days in 28, 4 sectors (6 hours) then 16.66 days in 28, on RYR's type of operation it's very easy to clock up 100 hours in 28 days.
But there are thirteen 28 day periods in 12 months and at 100 hours they can only work 9 of these periods so by the end of a summer a substantial amount of their pilots would be reaching their sell-by dates and needed to be sent on leave, put on light duties and/or grounded, we're at around that time of year now.
In my past recruitment another customer airline was Excel and rather than lay their contract pilots off of a winter we would place them with RYR for the winter months whilst RYR's own pilots were 'resting'.
I tend not to believe the excuse of a leave scheduling cock-up, RYR have been in business for a lot of years, they need to send these people on leave because they're burned out of hours, I've read of financial incentives (bribes) for pilots to work longer but hours in excess of the legal maximums cannot be bought.