Front left door lock gets stuck

Good evening folks!

I have an issue I really can't understand.

A week and a half ago I changed the door lock mechanism on driver's door and rear right door (the latter has been a nightmare, it was deadlock with the mechanical lock in, I had to demolish it inside the door). The driver's lock had a minor issue: it worked using the key but didn't respond to the electronic lock. Found that the actuator was ko. Both locks were aftermarket in brand new conditions.

So far, so good, everything runs ok, everything locks with the remote, used the car daily to go to work...

...until today: I went to work for the morning, came back home for the lunch break, closed the car, locked the doors as I do every day. When I tried to open them to return to work, nothing. All the locks make the usual noise, everything seems to work including the door pin, but the handle won't open the door. Tried with the key, with the remote, from the outside, from the inside, the driver's door won't open. All other doors were ok.

This evening I managed to open the door: I removed the rear one, started removing the key cylinder and it got unstuck, I could open it with the external handle. I disassembled the door panel, checked the lock, cables, electrical connections, the only thing that seems to cause the issue is the key cylinder. Reassembled everything without the cylinder, everything works; if I put the cylinder, after a few tries it would get stuck.

I disassembled it one last time (had to change the whole panel because of window cable broken), then reassembled everything paying extra care to every step, and now it seems to work: door locks and unlocks, and I can open it both from the inside and the outside.

I know I haven't provided clear informations to solve the issue...though, I was hoping in some suggestions to what to check next time it happens, along with some speculations on the possible cause...