The inbound flight has only stopped to refuel once so far. Passengers that had already booked were notified in February about the re scheduling, but I haven't seen anything on their website about it. GDFL has been operating the flight for the last few weeks.
According to Lanzarote residents, Jet2 are basing a 738 there starting this winter. I've been going to Lanzarote for over 20 years, and never had a fuel stop - yet