Nothing would surprise me at dealer service centers, especially not changing the oil but claiming you did. No implied warranty.I just changed the oil and filter on my 2019 3.6. I bought it used with 15k on it and it's at 23k now. The Chevy dealer where I bought it Certified it and claimed to have done an oil change on it before delivery and put a sticker on the windshield noting the next oil change. I noticed how clean it was all around the engine and suspect that the service wasn't done. seeing how easy it is to reset the oil life on the DIC, what are the chances that no service has ever been performed on this vehicle? The drain plug and filter were very tight and the oil was dirtier than I would expect. Also, I noticed that 6 quarts only brought the level on the stick halfway. I'll continue to monitor it.