I can’t provide a cure, but can only say that, if it’s a good negative, this shouldn’t be happening. Even though I have moved up to Silverfast ai Archive Suite, which is quite different from the SE version, I never had this issue with Silverfast 8se. That doesn’t help you fix it, only encourages you to keep looking. It’s not inherent in the Silverfast.
As an additional 2cents worth, a poor scan can’t be fixed in Photoshop, only made more palatable.. It’s not any different than trying to get a great print from a poor negative. The only way to get great results from a scan in PS, is to start with the best possible scan, with the best exposure and the best DR. Data never captured, either in the negative or the scan, cannot be reconstituted farther down the line, because it wasn’t there to begin with. Photoshop can’t fix it.
Good luck going forward, there’s a more specific solution out there somewhere.