I have 9 mp3 files that are all part of same album I purchased. When I add them to my playlist from the desktop app (Mac) they all show up there and play fine but only 3 of them sync to my iPhone. I have tried everything... and consistantly the same 3 songs get synced. I checked the tags and all 9 of them and they have identical tags. I have tried different WiFi, rebooting the phone and laptop, deleting the playlist, creating a separate playlist and etc... Nothing has worked.
This worked a month ago and now as I had to get a new phone doesn't work any more.