Hello Zarko...
This greatly minimises (almost eliminates) the probability of camera related light leak, but doesn't rule it out. In my experience, light leaks can happen sporadically between rolls of film shot with the same, faulty camera. But since you mentioned that your film reels feel a bit stiff, could you please have a look at the frame of film you attached and check if there is any sign of physical damage, or pressure where the marks are, at both sides?