1. 'Shiny' emulsions, like TMax 100 and TMax 400 are far worse than something like Ilford FP4+. It's as though the emulsion side has the same glossy sheen as the film base side on these films, which makes sense they'd perform worse, since they would be another reflective surface.
2. This happens with 35mm film as well. It is not isolated to 120 film. I just don't think the Epson V700/750 scanners are very well constructed machines for this reason.
3. I've had it happen with C41 color film as well. Portra 400 among others.
Obviously, taping negatives to the scanner platen is a pain in the back side compared to using the film holders, especially if you have many negatives to scan. But it does work.