I think I found the solution.
Settings > Lock Screen > Notifications > View Style > detailed
My theory is if u have it on icons only, the app isn't registered as being active by the lock screen. So if it is showed expanded out, the controls work again .
Hopefully this works for u all as well as it was really annoying me.
When you go into your Sound settings, The one that display each level of volume, Do you have the Media audio option selected at the bottom?
We recommend toggling that feature to address your concerns.
Let us know if this helps
Thank you all for the help! I have tried the optimization method and media toggle option AND the detailed lockscreen option. None of those options work. This is getting really frustrating. I can't control media on the lockscreen and cannot control media through bluetooth while the phone is locked.
Hello @Kapacahe, I can certainly understand your frustration. Make sure your Spotify app is not in your sleeping apps. Just Follow these few steps below.