After a day at the range, I was cleaning the bolt and noticed the retaining pin is bent. It looks like the firing pin has been hitting it and its bowed towards the back of the carrier.
Has anyone seen this before and what would make this happen?
The bolt/carrier came with a J&T kit, and only approx. 400 rounds fired total.

Same thing happened with my pin.  Also a J&T kit, hm...... Pin is VERY tight.  Have to use pliers when removing and screwdriver and hammer to reinsert.  And to top it off couldn't find replacement pin in my area.  J&T did sent a replacement pin.

Check out this thread http://www.ar15.com/forums/topic.html?b=3&f=66&t=162901

I didn't check the ref'd thread so this may all be a re run.

Most common cause of this being the hammer catching the front spool on the firing pin during the battery stroke.

Given that the bottom of the carrier is cut away exposing the rear quarter of the firing pin.

Could be an M16 (large front spool) firing pin instead of the correct AR15 (smaller spool) firing pin.

Could be a hooked hammer
Marked AR-15 (STD) and Sporter here
http://www.biggerhammer.net/ar15/hammers/
catching the firing pin.

Could be a trigger with a short sear face to trigger pin dim allowing the hammer to sit up too high.

Unload the rifle and cycle the bolt by hand slowly can you feel the carrier drag, possibly stop, when it moves over the hammer? Does that drag go away when you hold the trigger to the rear?

If so, best fix is a shrouded (closed bottom) bolt carrier.