This is unlikely to be a camera light leak. Because the problem appears with different lenses and different film rolls, the common cause is more likely the film, processing, or handling after development.

From the negatives, there appears to be residue or glue matching the red blobs, which points away from the camera and toward damage during processing or handling. Random blobs and smeared areas also don’t match the more typical look of a light leak, which often shows as edge fogging or more consistent streaking.

Most likely causes are:

• damaged or contaminated film
• poor lab processing or handling
• residue on the negatives after development
• old or improperly stored film

Best next step: shoot a fresh roll of reputable film and have it processed by a different lab. If that roll comes back clean, the camera is probably fine and the issue was with the film or the original lab.