There is definitely some noise associated with starting a cold hemi (piston slap/lifters), however this issue is a different issue. It is much, much, louder and can be felt as if someone hit the drivetain with a hammer once. I have owned two Eagle Hemi’s prior to this one. It’s not common to the Hemi. I feel it’s possible it has something to do with the transmission upgrades to accommodate the start / stop tech. The transmission has to be able to maintain hydraulic pressure to start the truck moving the instant the engine fires up. Another possibility is an issue with the starter. I do not have hybrid, however I assume they both utilize the same transmission. I would take mine in to get checked out, however my truck only has the clank about 1 in 15 starts. It occurred daily the first week or so, but it has drastically diminished in frequency.