When connecting to v18/Leia, music DB syncing works but only artists and album names are synced. No songs.
v18 changed JSON API and many apps have not yet been updated, including kodi’s own web interface (shows the same issue).
More details including kodi logs in this discussion:
https://forum.kodi.tv/showthread.php?tid=333097&pid=2746188#pid2746188
I see the same error triggered by yatse as this:
15:12:25.922 T:140249047422720 DEBUG: JSONRPC: Incoming request: {“jsonrpc”:“2.0”,“method”:“AudioLibrary.GetAlbumDetails”,“id”:“1529781145889”,“params”:{“albumid”:3889,“properties”:[“thumbnail”,“playcount”,“artistid”,“artist”,“genre”,“albumlabel”,“year”,“dateadded”,“style”,“fanart”,“mood”,“description”,“genreid”,“rating”,“type”,“theme”]}}
15:12:25.922 T:140249047422720 DEBUG: JSONRPC: Value does not match any of the enum values in type
15:12:25.922 T:140249047422720 DEBUG: JSONRPC: Array element at index 12 does not match in type properties