7880 scratching back (non-printed) on pictorico ultra-prem OHP film

I am wondering if anyone has seen this problem on their large format 7880, or equivalent, printer and has a solution.
Here is the situation and problem:
I printed a 21 step target on 8-1/2 x 11 inch piece of pictorico ultra premium ohp film using my 7880 with pro inks and HD PK. The target was printed on the correct side of the film. I noticed on the non-printed side of the film long, thin, “scratch” lines. These lines are very thin (needle like) and run the entire long length of the film (the same direction the film moves through the printer) and are evenly spaced about 3/4″ apart. At some of the 3/4″ intervals there appears to be more than one line, i.e. two in parallel very close together.
I have not yet contact printed this target to see if they show up on the print but I’d like to eliminate this problem going forward.
I have also posted this to the PiezoDN forum.
thank you!

Sorry for late reply, (I’ve been making ink) I replied on the dig neg forum.