I just developed a bunch of Delta 100 4x5 in Xtol 1:1. I've done this before and had no problems. The chemicals were mixed fresh and I use a tank with hangers. Same thing I've done for 100's of other sheets. I processed eight sheets and probably 6 of them had fine black straight lines on the negs. These are not scratches. Used several different lenses and 4 different film holders.
An example is posted in the Technical Gallery with both full frame and a small section. The scan is done to show the lines not to be a final rendition.
Any advise would be appreciated.