Update #2: Seems that it was my secondary screen the one that didn't show the color! Tried with another screen and I could see the progress clearer... perhaps a stronger color will make it easier to see across different devices?
Update: Seems to be an issue in Firefox, as I tried on Chrome and the progress is visible.
I just noticed that the badge progress on your user profile had it's style changed (don't know when but it seems that recently).
However, seems that the progress of gold badges is not working properly. If we see the Bronze and Silver badges, they are "filled with color" as you progress on the badge, however golden ones are not colored (just the border).
Here a picture illustrating what I say:
Is there a reason for this behavior?