bec puffed smoke?
 

Plugged my bec in and it puffed smoke? it still kind of works for a little while but then it shuts off.. Has this happen to others and is this common with the castle bec?

Did this happen when you plugged it into the battery or the reciever? How long is a "little while"? Like seconds, or minutes? The smoke may have been the capacitor going nuclear, but I'm not sure how that relates to the behavior you're now seeing.

It actually still works till I put load on the servo's then it starts to become intermittent.. An yea when I plugged the bec into the batt, thats when it went poof..

You were lucky that it just went poof with some smoke, usually they will fail without warning and than you will lose your Rx and servos, myself I dont trust CC BECs, if I use a BEC I use Western Robotics. The only way to be safe is to use a Rx pack,