Why are songs disappearing from my albums and showing up as "unknown artist"

[Darcy Wells]

I own an A5, bought it in 2017. I digitized my music CD on my pc and transferred most of it to the phone. Now 99% of the music shows up just fine but in every album, the first song and sometimes the second are missing. All the songs are there but they show up under "unknown" artist and or albums. I looked at the "music" file from my pc and all the songs are there, titles, artist name, album, etc..... It's all there but the "play music app just won't recognize them. The fact that this hits every album, and only the first track (in most cases) looks like a bug to me.
Help?