A clue may be your discovery that only the Album tab in the song files had a value. That does not sound normal as there are usually several tabs filled in. That said, the fact that an album was associated with its song files in the Tabs should have enabled the album to show up in the Audio, Albums view. Does the Artist for these songs show up in the Audio, Artists view? BTW, the icon in the upper left corner of the Tab Action Window, when clicked, shows a pulldown window with tab view choices. It might be set on “View Default Tabs.” To be sure you are seeing all Tabs, select “View All Tabs.”
You asked about reprocessing the misbehaving files. You can try re-importing the album with the Tools, Import, Import a Single Folder method. This is easy enough to do except for one possible complication that is easily overcome. When I tried to re-import an album, JRiver displayed a message that 0 files were imported.
After trying a few more times and getting the same message, I found out that JRiver will not re-import files that are already in JRiver. So, if you get this message, you have to delete the song files in JRiver first, then import those files again. If there is a setting in JRiver that allows re-importing without first deleting, I am not aware of it.
I have not heard of file names, extensions, etc. causing the kind of problem you describe but I’ll be on the lookout for it.
I wonder if it’s possible that something is wrong with the original files or download process from HDTracks. Maybe the album can be re-downloaded from their site or they can be contacted for a solution. I say this because it sounds like you have processed albums from HDTracks before and gotten them into JRiver without incident. So maybe this one download is defective.
Please let me know what you find out.
Phil