Moving-copying tracks doesn't preserve line style
When copying or moving a track that currently uses the original folder's line style, the new/moved track will use the destination folder's line style. In effect, that is not a 1:1 copy (although, granted, data-wise it is, because it's copied with the "Use folder line style" flag preserved).
I'd argue that the new/moved track should keep its actual current line style. If that's not intended, it's always easy to revert to the folder line style - but recreating the line style of the original folder manually is much more of a hassle.