Laptop vs mobile playback availability is different: Confused

[Lizzardicus-Spork]

I'm not understanding why songs that are *already on* spotify (as in publicly available for listening) will play on my mobile, but won't play on my laptop (windows 10). It just keeps saying the song is not available, if you have the file on your computer you can import it. I don't have the song on my phone either, yet it'll play there without any unavailability prompts. I don't get it. Shouldn't the songs just playback with the spotify web player on my laptop (which IS properly enabled) if they're already on spotify as available content? And these are songs that are NOT blacked out as unavailable. I'm not understanding. This is not happening with all songs, but it's happening a lot, when, based on my understanding of how this all works, it shouldn't be happening at all. (note: network connectivity NOT an issue here, and using the exact same account across both devices)