Morning guys

I have a quick question about afterfiring (I don't think it's backfiring). Does it damage any engine components particularly the turbo or cat?

I am running forged rods, stock 15g turbo coupled to a 2.5-3" decat turbo back exhaust, me4.4 ecu and vxr injectors. It was tuned by tim and Ryan and seems to run great but on over run after releasing Throttle even if driving gently I get some grumbling/crackling and occasionally a loud pop/thud mostly between 2-3k rpm. Worse in damp weather oddly. I don't know much about the tune I'm running. It seems to have become prevalent since moving from the rica map to the new one with newer ecu and exhaust.

As much as I actually quite like the noise I am just after some reassurance that it won't damage anything as I am looking to introduce a cat soon for the mot and don't want to wreck it or the turbo almost immediately!

Thanks guys