Scratch on negatives - what went wrong?

A question to all the experts here. I just developed and scanned a batch of negatives, and quite a few have long thin scratches across the negative. It looks like this (scanned as positive):

http://www.blackandwhitegallery.de/sample/scratch.jpg

This is the first time that I see these kind of scratches in so many negs. What did I do wrong?

The negs are TMAX 400 and they were loaded in Grafmatic holders, developed in Jobo 2500 tubes. That is my normal procedure. What I did different this time: the negs are from a longer trip and I unloaded the exposed negs from the holder and stored them in an empty sheet film box for the trip home (no x-ray involved).

I guess the scratches must be related to the unloading and storing the sheets in the film box. I don't think it is a faulty Grafmatic because the scratches are visible on sheets from more than one holder.

Any suggestions how I can avoid this in the future?

Thanks in advance

Thomas: It is surprisingly hard to scratch dry film, so pretty unlikely that this could result from loading the grafmatic or taking the film out and putting it in a box. A grafmatic scratch (I've never had one) would result from shuffling the septums and wouldn't be diagonal like this. I think it has something to do with handling wet film, but since I only use trays, can't comment on a Jobo issue.

Reversing it like that makes it more difficult to figure out. But if I can imagine your negative it is mostly clear with a black scratch across it. In that case it would be a scratch in the base side.

Check your Graphmatic and your developing setup for burrs that could scratch the surface.