That and G. R. R. Martin. ASOIAF is never going to be finished.

I mean he has other stuff, but him completely ignoring finishing his biggest series is frustrating.

Warforged Ranger

I use Planet Oat and haven’t really had this issue, I only notice it if my coffee has been sitting too long. I used to use the Aldi store brand before that and that had a similar issue to what you’re seeing.