Ah, I see. Since a color isn’t set on the flair for the black cross, it’s incorrectly picking up the link color in the topic map.
This is fixed in
https://github.com/discourse/discourse/commit/1d4e9b08ade008d2ba593213cf20ec57ea287ac8
If you want to fix this immediately you can set #222222 as the flair color for the group with the black cross.