$bp(vibrant, ni(mi(package), bicon))$ does not always immediately provide the color of the current icon on skipping next/previous or when track advances automatically. Sometimes it changes immediately, after a random delay, or not at all. Please see the attached test image for an example. Activating play/pause results in an immediate update, but not toggling visibility.
I do not have this problem with $bp(vibrant, mi(cover))$. it evaluates immediately. The problem is also not with $ni(mi(package), bicon)$, as this evaluates immediately to be displayed as the cover in my widget. It appears that the $bp(vibrant, ni(mi(package), bicon))$ formula is evaluating the previous icon's bitmap.
I was using mi(cover), but several of my music apps don't provide it. They all provide the notification icon.
Thanks for a great app!
KWGT v3.29 under Nova Launcher on Samsung Note 8 SM-959U, Xfinity Mobile