Those measures usually occur when the scanning software misinterprets what Finale would otherwise express as layers. SOmetimes the problem is that the offending note is not actually in the measure where it appears but in the prior measure. You may want to use Speedy Entry with the "Check For Extra Notes chosen in the Speedy menu. You can then choose to crop the measure to just the first "legal" beats and then reconstruct the measure as needed. (This process is why some users advocate typing scores in fresh rather than scanning them, but I've found it depends on the complexity of hte scanned score and hte patience one has for cleaning it up.)

I advise trying this process on a copy of the original scanned score so you can revert to the original scanned-and-interpreted version if it all goes south.