Sounds very similar to my 2010 SESG failure at 24K miles. Similar noises. First, the dealer replaced the compensator which was bad. Didn't eliminate the noise. When they tore into the motor, they ended replacing the cams, lifters, pushrods, pistons and jugs, and reworked the heads. Although they weren't sure what caused all of the damage, they thought it was probably a failed lifter, but also was much carbon buildup on the heads, pistons and cylinder walls. Only mods are slip-ons. No headpipes, tuner, etc and maintained by the book.
Again, best accessory I ever added was the ESP. HD initially denied the claim stating this was "normal wear and tear". Dealer claimed otherwise as they have serviced the bike regularly and the MoCo took care of. Been contemplating V&H power duals, SERT and a good tune, primarily to reduce the heat, that I think leads to early failures. However I am a bit cautious as to whether the mod might give the MoCo grounds to deny a future claim.
Be interested in hearing how the MoCo treated your claim.