Problem Rear door lock


Hello, I also have a problem with the rear doors. In one week, both rear doors remained blocked from the inside (that is, I cannot open them, at an interval of 2 days). I open them from the outside without any problems, the child safety is disabled. What could be the problem and what do you advise me to do? I have to turn the key a lot to deactivate the child safety (if I don't know, that's why I'm asking - maybe I didn't turn it enough). I mention that when I saw that the left rear door was locked, I automatically looked at the position of the child safety lock on the right door and I kept "doing" them.