I've read the arc. I mean, it's been a little while, but I read it just the same...
Anyways, this wouldn't be the only time that two feats conflict. It happens constantly, and if anything, it could simply be attributed to CIS on Danger's part, or ignorance on the Writer's.
All we really have to go on is that it seems that Emma CAN be pierced by Vibranium weapons. If one later bounces off her, then we can question the validity of the feat that you posted.
Since she's never successfully defended against one, it's pretty safe to assume that she can't. ๐ฌ.
Still doesn't mean Cap wins - just that he has a chance.