I am in the process of making a YES warranty claim for my 2016 Vector XTX that has a blown rear shock at 639 miles. I am going to use the above information to better inform the dealer doing the repair and submitting the claim. They were unaware of the updated shock (8LB-47480-00-00) until I sent them the attached Tech Exchange document below. I would note that the date of the document is 2/23/17 and shows all the Apex and Vector models for which the updated shock is applicable, which in and of itself contradicts what Yamaha told you. (I'm assuming you spoke with them after that date). I'm currently riding in the Rangeley, ME area and I was fortunate that the shock did not fail until the end of yesterday's ride as I was backing up, positioning the sled to load onto my trailer. When it collapsed it also sucked up and tore off the snow flap. I'll post when I get a response to my claim.
Did you get this fixed under the Yes warranty? Did they put in the updated shock and cover your snowflap?