Belt question

I have a new (6.0 hrs) Gravely Pro-Turn 460. Mowed about 10 feet today and suddenly no cutting. Opened up foot plate & discovered drive belt came off. My question is should I go through the trouble of removing the PTO belt, reinstalling the drive belt, reinstalling PTO belt without first knowing why the belt came off after only 6 hours of use. Obviously, this should not have happened in the first place and wonder if it might be best to have dealer service dept check it out before going through the effort. Haven't replaced a belt on a Gravely so not sure how much effort is involved.

Duh, no brainer. Have the dealer do the diagnosis and work under warranty.