It seems like a pretty easy thing to ignore.
It used to not have an icon at all... so this is a step in the right direction.This is not a "problem" per se.
You know how when you bookmark a page, a little icon exists in the bookmark list? On both Chrome and Firefox, the website's icon is currently a black circle with a "G" in it.
Here it is on the tab also:
View attachment 7585
Not exactly earth-shattering, I realize.