Yes I am 100% sure. If I kill the app or swipe away the Spotify play notification bar I get the clock back again on the LED cover. I can also disable the media controls totally by removing some Spotify notification options in settings. (Don't remember exactly which options it was ...)
This fix also solves the media control LED for other apps like Google Music which I use sometimes for MP3s.
The software on my S10+ seems to be from 19th of July if I read in settings.
I received the update and it has fixed the problem with the music controls on the Led cover. Note, with Spotify, samsung's music app and Google's play music app I have to clear them from the recent apps to remove the music controls. Before the update this would not have worked