Apple Music is bad with this too. Even though it's what I use for streaming, I simply do not trust it to keep things locally if it decides it might have a bette

Apple Music is bad with this too. Even though it's what I use for streaming, I simply do not trust it to keep things locally if it decides it might have a better idea about whether I need disk space than it does. I use Castro for podcasts (inbox/queue works great for maintaining local downloads) and Doppler for music.