Originally Posted by sdsearch

Did each of you apply in private aka incognito mode? If not, it could be that your browser confused cookies between the two submissions if you both used the same browser on the same computer (and/or your browser confused cookies from previous visits to another link) and that was the problem.

I recommend always applying for any credit card with a private aka incognito window, as it avoids cookies from any previous browsing from confusing the bank about your offer. There are horror stories aplenty across FT (at least at some other banks) where someone looked at link A, then pulled up link B, applied for it, and the bank says they for link A !