Advancement toasts with transparent backgrounds glitches

When trying to create a transparent background for the Advancement Toasts, some odd bugs occur:

1. The transparent background only affects the topmost toast in the list. All preceding ones no longer have theirs as transparent.
   
2. When chat is opened, all transparency of the background disappears, including for the first toast.
   Without chat open:
   

With chat open:

Ideally, the toast's transparent background should work for all toasts regardless of order in the list, and whenever chat is not opened.