The difference between page background color and progress on golden badges is so miniscule that I find it hard to see it at all. I see progress on bronze and silver badges just fine, but the contrast of gold badges is so small that I need to check numbers to know where to look.
My sight is far from perfect and I'm protanomalous colorblind, but I don't think this affects the contrast enough. Let's do the math.
Bg color R G B H S L page 255 255 255 0 0% 100% bronze 209 166 132 26 46% 67% silver 180 184 188 210 6% 72% gold 255 250 230 48 100% 95%
The lightness value of bronze and silver badge progress backgrounds is around 70%, while lightness of gold is 95%, which is displayed on pure white background with 100% lightness. This is probably a mistake as numbers are clearly inconsistent.
This applies to all websites, both to badges displayed directly in profiles and to the popup for choosing a badge to track.
P.S. Even if protanomaly affects the contrast, it's one of the weakest types of color blindness, so people with other types of color blindness will be affected even more. Also slight differences in contrast are very dependent on monitor settings. Almost nobody has perfectly calibrated monitors.
[Edit] While this question turned out to be a dupe, it's higher quality than the first one, has more info and more upvoted already, so I'd rather close the other way.
[Edit 2] Considering this question is bug in status-review and the other one is discussion, I find it counter-productive to close this question instead of the other one (who was first doesn't matter).