The replays immediately showed that the two men had a clash of heads that left Yahya knocked out prior to Bedford landing any punches. The correct call in that situation is a "no contest" due to the result being caused by an accidental foul, and the officials got it correct.
Unfortunately for Bedford, he didn't see it coming. He was celebrating as the result was announced by then lost his cool, calling the decision ridiculous.
As Dan Hardy tried to explain to both men that it was clear that the headbutt caused the knockout, Bedford simply did not care. He yelled over and over about "knocking him out" and saying he won the fight. Bedford and Yahya exchanged a few shoves before the situation calmed down as Bedford seemed to think his not being knocked out was proof of a win.
It was an embarrassing moment for Bedford that was met with reactions such as this by the UFC on Fox Twitter account:
I don’t understand Bedford’s case. You can’t win via headbutt, dude. Calm down.— UFCONFOX (@UFCONFOX) April 11, 2014
Bedford took to Twitter to call for a rematch: