Complilation album not loading all tracks together in the same album

Trying to copy few mixtapes from pc onto itunes to play in apple music. running into the same problem to varying degrees regularly in that not all tracks from the same album are copying into itunes in the same way and order.

For example the album has 20 tracks. 2-19 have all copied as they should but track number 1 is displaying as a separate album.

I then tried to sync a different album but then all tracks were displayed as individual albums.

any ideas?

thanks