Log Error Messages Not Understood

[Budgie]

I know I am pushing my luck having failed to read (please forgive,) the library paragraph on playlists but once I added 8 to the extension .m3u8, the errors disappeared from the log. Am I right in assuming that because the NAS and control points are all running on variants of linux, the problem only manifested itself in the windoze machine running minimwatch and the playing system would not have a problem?

My error log is now down to only a few lines but three have me stuck as try as I might I cannot see the causes:-

Error: group contains tracks that aren't consecutive: Cantata, BWV 62 "Nun komm, der Heiden Heiland II" in album Bach_-_Gardiner_Cantata_Pilgrimage_(Disk_52)_BWV_61,62,36
Error: group contains tracks that aren't consecutive: Auf Christi Himmelfahrt allein BWV 128 in album Bach_-_Gardiner_Cantata_Pilgrimage_(Disk_20)_BWV_43,37,128,11
Error: group contains tracks that aren't consecutive: Orfeo & Euridice in album Gluck:Orfeo & Euridice

I cannot see any non consecutive tracks in file names or tags. Any suggestions please.