For the 1st and third picture I have no explanation but for the middle one where the sprocket marks appear on the edge of the frame, I have had these myself. I process all of my films, B&W and colour myself and have experienced these on a few films, but never with B&W. I do not know definitively what causes it but I can make a reasonable guess and that is beach fix on it's last legs. Labs usually have a auto replenishment trigger in their mini-labs and this should take care of any replenishment needs.
What I also have on my problem (not every film but occurring randomly) is on the strip of film between there are sometimes within about 1-2mm of the preceding frame areas where the film does not appear to have developed evenly and generally has a brown tinge This may happen over 3-4 frames and the remainder of the film is clear. of problems.
If it were a camera with a horizontal travelling focal plane shutter I would think of 'shutter bounce' but it occurs only on my cameras that have vertical travel shutters.
There is also a known phenomenon called 'developer drag' where on a negative with a deeply dark area which of course on the negative is almost clear film. If this area is next to an area of a normal toned negative, you can get this 'normal' area, showing strips where the film is over developed. Not enough to see just looking at the negative, but enough to be visible when it is printed. My last experience was with 120 B&W film in a Bronica ETRSi where I pictured snow drifts with fence posts sticking out of the snow. I put this down to insufficient agitation when using a Jobo Processor, but I have no definitive proof this is the cause