Three days ago, while advancing to the next frame on a roll of PanF+, the winder did not stop but kept going. After missing a couple of frames, I winded the whole film like that until the end. The next day I tried another film and it was fine, the back stopped at each frame. Yesterday I tried a roll of FP4+ and the problem reappeared.
That's on a new A12 back bought as a kit with my 501CM last Christmas. Everything has been treated like a newborn baby. I load the film carefully making sure that I follow the "Ilford mark" and also press lightly at the loading spool so it packs tight.
The whole kit was seeing by a technician in the beginning of summer and the back was in order. Should I take it back to him?
Even though it is still in warantee, the equipment has to fly from Crete to Athens and with inspection and repair we are talking about two weeks, so I would like to avoid it if possible.

Any advice?