Sounds like a valve guide issue.
Return to dealer but not before you take a few videos of the event with you as proof.
Post one of them to You tube and link it here.

 

Yeah, that's what I'm thinking too. It just seems weird since it only has 20,000 miles. Last time I tried to get a video, it wouldn't do it. I'll keep trying though.

Any thoughts on whether worn valve guides can cause long-term damage, or just a minor inconvenience?

 

My experience says
blue smoke is oil
Black is a rich gas mixture
White is water.
If conditions are right water can condense in the exhaust pipes and produce white smoke when you restart. I also recommend you have the dealer check it

 

Worn valve seals won't repair themselves, they will just get worse with time it that is in fact the problem. Puff of smoke and oil consumption will be the issue in the short term, but won't do any mechanical damage. I don't understand why such a new car with low miles like yours would have this problem. Have you been using the correct oil? Have you been using any oil additives? Regular oil changes? Do you drive the car hard?

I would press to have the issue fixed by the dealer under warranty, but they will probably tell you that "it is within acceptable limits".

P

 

When you start it in the morning take a look at your driveway directly under the tailpipe. Do you see any black sooty/watery residue? This is a sign of excessive blow by. If your seeing black spots then most likely something not setting up right in the rings or valves.

If not, then it's just water.
Try taking the car out for a nice drive. Get it up on the highway and run it for a good 60mins. Let the oil get to temp and boil off any residual moisture. Let it sit for a hour or two then start it back up. If your still seeing white smoke then check compression cause something is not right in the head

 

The dealer is going to look at the car on Friday.

I haven't used any oil additives or driven it hard either. Hopefully it's something easy to fix, although the guy in the service bay said it could be something like a busted piston ring too. He said that would require a new block, and I'm guessing it would come from a junkyard and not a crate.

I have HondaCare out to 2018, so I'm not too terribly concerned since I know I'll have a working car until then, but it would be nice if it were a simple fix.

 

White smoke is water vapor. Is there any smell associated with the smoke? A sweet smell would be engine coolant. There may be a head gasket leak. You may have better luck after the vehicle has been sitting longer, in colder weather, or if the vehicle is parked at an angle (toward the left or right).