Neg scans issues with banding

I have an Epson 750 MPRO I use for print as well as neg scans. I am running into some serious issues with banding while doing negs scans of 120 film. I am using the standard 120 film holders and I know they are not the best. I do this step primaritly for proofing purposes. These are not high quality scans.

The first image shows the banding on the LHS and you can clearly see the hasselblad signature dents being repeated in those scans. At first I thought it may be reflection in camera during exposure. It's not.

image Stony Point 12 shows the banding.

image Stony Point 12a is the same neg only moved to the other side of my neg holder and also turned 180 degrees. Problem is still there.

image Stony Point 12c was a neg scan with the neg laying directly on the scanner platen. None of these are hi res scan, but clearly the problem goes away when the neg is in direct contact with the platen.

Any idea why these scans are doing this?? I do not get this problem with 4x5 film in that Epson film holder for the record..

I am assuming the neg is 6x6. Is there any way you can seperate it from the others on the strip and then turn it through 90 degrees. If the banding also rotates then I would assumie it is something in the film.

ANother suggestion is have you tried to adjust the height of the film holder. Although there is only limited adjustment on the Epson holder it would be interesting to see if the problem becomes more or less pronounced.

Finally, have you tried switching software. Is this the Silverfast software or the Epsonscan? Try the other and see if you get the same problem.

I haven't seen this before but the above might help narrow down the cause.

Since you don't get it when it's on the platen, it seems to me like a holder issue. Probably the film is not completely flat and bends down a little. Such small things may have pretty pronounced effects. For example, my Canon 9950F doesn't have a completely flat scan bed. To the left and right of the glass are plastic strips holding the glass down. This is stupid, because it means that whenever I put a print down on it that doesn't fit exactly within the window, it will bend upwards slightly at the sides and cause light creeping in from the sites and light from the scanners light source being reflected not straight down. It is always visible at the sides of the scan.