Same issue here. I good chunk of music that I have liked on my phone isn't showing up in my "liked songs" tab, or showing up as liked at all on my laptop. The last liked song it saved on my laptop was from MARCH 9TH. It is currently AUGUST 8TH. That's five months worth of liked music that isn't there on my laptop. PLEASE fix this soon Spotify.
As of today, 8/28/19, this issue has been fixed for me. All of my liked songs are showing as liked again. I didn't do anything to fix it, it just fixed itself, so I don't know if Spotify finally fixed the bug or what.
I'm having the same problem, except I also can't save new songs, and I think I've been having the problem for longer as well. The issue still isn't fixed for me. I have Google Chrome on the newest version, and it's been a couple days since other people have reported it being fixed.