Local Files not transferring from laptop to iPhone

[ze11]

Plan

Premium

Country

U.S.

My Question or Issue

I've been trying to add some local files to my phone for a while now, they'll show up fine on my laptop and play perfectly fine as well. Then when I make a playlist with those songs and download it on both my laptop and phone, not all the songs will show up. I've tried remaking the playlist multiple times now and most times different songs from the album will pop up. Any help, or is this local files stuff just all luck? I downloaded another album through local files a few months ago and it worked perfectly fine.