UPDATE:
So finally after lot of diagnosis, they found that the fuel pump has some sugar like substance in it which was preventing the smooth startup. They changed the whole fuel pump, vapor canister, purge valve, tube fuel filler and tube recirculation . It seems someone would have added that intentionally. Since i always fuel up at Costco or BP. Just twice at KWIK Trip to check whether it made any difference. My truck stands in private parking lot always and the startup issues were from the very first fueling of the truck so it concludes that if something was done then it was at the dealer's lot or at the plant even before purchase was made. I got when the miles read 18. So the mystery continues. I am going to fill the tank up when it is near empty, so TEST in progress.
Dealership did work with me in the process and RAMCARES did reach out promptly. I hope it is a good ending and I don't want to see both Dealership or RAMCARES now. Only interested in OIL CHANGES.