Loud popping exhaust sound occasionally with cold start

[My_first_RAM]

Has anyone noticed a really loud pop sound from their exhaust during startup? It’s not all the time and I can’t figure out when or why it’s happening. I have a flowfx muffler and resonator delete, but it did it when everything was stock. Every once in a while it’s super loud and my wife even asks “is it supposed to do that”, and this coming from the person that didn’t even realize when I upgraded the exhaust.
Since it did it when everything was stock, I’m wondering if it’s a slight leak around the header or the cat that changes with change in the weather.

 

[brakervan]

Do you mean when you're slowing down and downshifting? Those pops and cracks are unburned fuel igniting on the hot exhaust. I've never heard it when you downshift and immediately get Kodi nox heavy on the throttle.

 

[SurfRebel20]

There's a thread on this and it seems to be the drive shaft for the 4wd . There's a video of someone's and It seems the shaft very briefly engages and jerks on startups. Mine does the same noise