iOS Playlist issue with not showing all songs

Hi !

I have the following issue with synced Playlists on iOS:
I have some albums of an artist completly synced to my iOS device and now I also created a playlist which uses 12 of the songs that are already synced but also 3 other songs of the same artist that where not synced before.
After creating the playlist I started the sync and waited for completion.

The issue is that only the 3 new songs are shown in the playlist afterwards but not the 12 songs that are already on the device.
However I can see that the total playlist time shows as 1h 3m and 15 songs.
Anyone knows how to fix this issue ?

anyone can help here ?