Streaming eats into my device's available storage capacity

Has anyone else noticed that streaming music is eating into their device's available capacity? I have an iPhone 6+, and I have noticed that in Settings -> General -> About the "Available" keeps shrinking the more I stream. I am NOT downloading the songs for offline. At first I was adding artists and albums I would like to listen to to my music, Apple support did tell me that adding artists and songs to My Music does not use any storage. But as an example, the first night as a test I decided to add every Nine Inch Nails album (because i know there are a lot of them on Apple Music) to my play next cue and then went to sleep. When I woke up I found that my available capacity dropped, not a little but, but by a full 4-5GB! Yesterday, I did some more tests and I have found that on average, every 5-6 albums I stream (depending on how many songs are on an album) it eats up 1GB of available storage.

Talking with Apple Support they told me it is just a cache of the songs and that cache would delete itself when i quit the app or restart my device. I have done so several times and I continue to lose available storage. I have asked Apple support a couple of times to clarify how to clear the cache but they have no answer, so I'm hoping someone here has found a trick. I can see my history of songs played, and I really feel if i can delete that maybe the cache will delete as well, but I have only found a way to clear the upcoming songs playing, not what has already played.

At this rate assuming I only stream 5-6 albums a day I'm set to run out of storage on my device in a week. I'm really considering trying to flood that to see what happens when I do run completely out of space on my device. But If anyone has a solution that'd be great.

j.