Light leak??

I developed a roll of HP5 shot on Friday... and all images are affected by mysterious strips;[ It happens second time, although the pattern is different (one roll has regular vertical, lightly skewed strips, on the other the strips goes radially in a fan shape...).

Any ideas what that might be? My guesses: light leak (I checked the backs and the seals are fine; besides, the lines are slightly diagonal and previous film was OK), me doing something wrong during development (but I did everything as usual - and all previous rolls are clean), or something wrong with the film itself (but 2 different films, from 2 different sources... no way)

There was light leak on the sides(cropped out) caused by paper backing being too narrow... so it was not protecting the film properly on the spool - shame on you Ilford!

Examples - shot under the same conditions, with the same settings - one with clear strips, the other one (2 frames earlier) almost clean...