@Robert.Mauro may be able to give more info on the warranty issue.
My take is they sold you a vehicle with a warranty and it seems like you are noticing an issue with the suspension. The shocks/struts may be worn and need replacement which is not unheard of with the ascent. If the warranty is no good and you are otherwise happy with the car, asking they cover the strut/shock replacement in lieu of the warranty may be a good move. It is really up to you where to take it, you may also want to give Subaru a call at 1800 Subaru3 to see what options are available for you.