I reckon you saw a pentester using HTTP request Hijacking.
http://www.skycure.com/blog/http-request-hijacking/
In short: Twitter/BCC news app requests a feed, one spoofs the DNS request for the feed to a third party, at the third party you put a 301 redirect to a specific site (e.g. notyourtwitter.com), and the application gets the feed spoon-fed from the wrong place. Now, you would think this would all end once the iPhone moves to a different place, dns cache expires and the situation would resolve itself. But no, the application itself is caching the 301 redirect to the same specific notyourtwitter site, long after the fact. The link above describes the exploit in more detail. It's not an iOS fix that would resolve this, developers themselves need to fix this.