2013 Kia Sorrento Smoke?

Smoke from Exhaust. Should I worry

Hey Scotty, I've been watching your show for about 8 year when I need to figure out how to do small jobs on my 2005 Saturn Vue with an I4 engine. I recently donated that car to Kars4Kids.com and purchased a 2013 Kia Sorento SX with a 3.5 V6 engine. I started experiencing a puff of smoke at start up from my exhaust so I decided to take it to my mechanic (an honest mechanic and family friend) to take a look at it but he told me not to worry about it since it wouldn't show while driving and it's only at start up with no noise and the car runs fine. He also suggested to take it to the dealer since i just purchased it only a month from seeing him (Feb 22nd 2018 was the purchase date). So I took it to the dealer and they had it sit for 4 hours before starting it up and saw no smoke at start, found no oil and coolant leaks, and said the pressure tests were fine. Occasionally I still get that little smoke on startup that I would describe as a puff. Am I worrying too much or is this normal?

I've been checking my oil and coolant levels and everything seems to be fine. No leaks.

I made the mistake of putting gas from Sun Corners or Sunco, I've always thought it was a Sunoco and overlooked their sign. Could cheap gas cause this?

Here are some videos and a picture of my coolant level.

Just to update, I took the car back to the dealer and because the mechanic added an oil additive for engine sludge that he notice, the sludge clogged up the intake manifold and PCV valve which would burn the oil on start up. Both Intake manifold and PCV valve were replaced for free. All is good now.