This bug has been bothering me for a long time as well. It is still not fixed on 19.0.149.
I think it is due to the mishandling of the track suffix (;1 ;2 ;3 ;4 ...) for SACD ISO track names by [Tools]-[Library Tools]-[Rename, Move & Copy Files...].
For illustration, let's assume I want to move my music from D:\Music to M:\Music.
After the files are copied, I want to use the library tool to update the database to point to the new drive letter.
Let's try on a single SACD ISO album at M:\Music\album_name.iso. I select the album under Audio and start the [Rename, Move & Copy Files...] library tool.
I select "Update database ... (no file rename, move, or copy)", because the iso file is already at the new location on disk M and I do not want to move any files.
Then I check "Find and Replace":
Find what: D:
Replace with: M:
If you look in the Original column, you will notice the track number suffix is not showing. For the first track, you see album_name.iso instead of album_name.iso;1
The drive letter is correctly renamed from D: to M:, but all track name tags now lost their track number suffix.
If you try to play, you will "Something went wrong with playback".