Yes, the behavior you’re describing is what I’d expect to see when Roon is scanning a watched folder and encountering files other than actual track files. (I think this is typical of most people’s libraries; it certainly is for mine.)
You shouldn’t have to do anything else. One of the Roon support techs should be along before too long.
Just a guess, but at some point, I think you’ll need to identify some track files that have been scanned but not imported, as a basis for homing in on the problem. The support guys may also ask you for this info.