this has been there for a long time, but I discovered Spotify Community not so long ago (3 weeks) and as I see some topics with this weird behavior from 2019 without any resolution (yet) as I still have this issue on my account, I decided to open one to get more info on that.
My account is not so old, (from November 2017 if i recall correctly), and I discovered it like in mid-2018,
during that time, I was listening a lot on my windows laptop, and it was then happening a lot more frequently then the 2 following years (from 2019 to 2021) where I was only using it on my smartphone.
this last year (mid 2021- now), I started again to listen to spotify on a windows laptop (different then the previous one) and I saw those songs started to come again in my liked list.
I checked any properties/follow/relation that I could have on spotify with that Artist but nothing seems to be the root cause of this behavior.
I usually log out from current logged in devices, I did it recently (october 2021) and the behavior was still there.
As I say, this is only happening when I use Spotify on a windows laptop. I never get that issue while using it on Android/iOS