Exhaust brake wont cause that if it sticks and way too old for regen - besides, it doesn't look like that.
You probably have an 03 eng/chassis which means early common rail.
Since it's not doing it now it will be very hard to diagnose
Here's a couple of thoughts though: if it was a stuck injector it could quickly burn a hole through a piston. Could have been a low boost issue too but it would be nearly impossible for that to fix itself. However, low boost with that much fuel will result in extreme EGT - enough to melt pistons in 30~60 seconds. I just tell you these things so you are aware.
You also might check the 2 piece exhaust manifold for cracks - they are fairly common on the 8.3's.
Good luck, hope it's just a sensor or some other cheapy fix.