Spotify clogging up my phone's internal storage even though I'm just streaming.

[ldn2016]

New phone: Huawei P9 lite
Version of app: Android 7.8.0.607 armV7

Same old SD Card problem spotify refuses to fix, on the verge of cancelling subscription tbh. Not much internal storage space, 64GB SD card w. lots of space, spotify refuses to save anything on my SD card. 

So I just use spotify for streaming. Not ideal but oh well.

I checked my storage info after an hour of streaming and spotify had used up 1.25GB of internal storage. I went into airplane mode but couldn't find anything available offline.

1)  What is it downloading to my phone? Not songs.

2) Surely it's not using 1GB plus internal storage as cache? That's ridiculous and excessive. 

3) Can I ban spotify from saving anything to my internal storage? It can save whatever it wants onto my SD card, I just want to ban it outright from saving any music to my internal storage.

* There's some mod here who keeps insisting on past similar threads that we're all collectively confusing RAM with internal storage. This has nothing to do with RAM. The stupid RAM comments just derail every past thread.