I added an album ELZA by Elza Soares, downloaded from Bandcamp in flac. Roon shows all tracks except track 2. I have made certain that track 2 is on the NAS and that JRiver and Groove see and play the track, no problem.
I tried everything that looked relevant in the edit functions, to no avail. Doing a search on Roon does not show the missing track anywhere.
I am using Roon 1.2 build 154 on Windows 10.