local files artist and album fields are greyed out and will not sync with iphone if in a playlist


when I add some local files the artist name and album name are greyed out.  They are not protected files (I checked DRM).  They play on the PC from local files or a playlist, but when I add them to a playlist and make them available offline, they do not sync with my iphone playlists.  They appear in the playlist, but will not play, an error appears when I try to play them that explains how to sync them (which does not work).  What's really strange is that some songs from the same artist and album are not greyed out and those do sync on the iphone.  What's up with this? Attached is a picture of local files, showing some files not greyed out, others are greyed out.