This is the first time since July 26th that price has tested the 50-day MA. The Fibonacci projections are based off of the most recent seed wave (low of 09/06 to the high of 09/08). Price seems to have met with some supply at the confluence of this 50% Fib. projection and the 50-day MA.
And if you're not convinced then what does this chart below tell you? More than half of today's volume came in the selling frenzy that occurred in the last 30-minutes of trading: