The warranty for the spindle only on the V2-50 is 3-months from time of delivery to you. The warranty for the rest of the machine is 1-year from time of delivery to you.
It is common for machine tool manufacturers to warranty the spindle for less time than the rest of the machine as they are the most prone part to improper use. If you use your machine during the first three months of its use and there is a factory defect then that should become apparent during that time. If you use the spindle properly then it should last and you shouldn't have any issues. Note, that with proper use the NSK spindle is rated up to 3,000 hours at 50,000 RPM.