The violet spots look like a leftover from the anti halation layer. With Orwo NP15, you will need an extended fixing time in thick acid fixer, or a 10% sulfide bath for the removal of the anti halation layer.
Old NP15 in 35mm is often usable, NP 20 and higher sometime suffers fogging. 120 film may have issues from the backing paper reacting with the emulsion.
View attachment 381697
Fogged Orwo NP20. Not usable.
View attachment 381698
Excellent Orwo NP15, Exp. 1991.
Developed in Fomadon LQR, 1+10, 7 Min.