If this is a brand new machine, the rust on the pulleys indicates to me that it was left out in the rain, or was pressure washed or ???. Given that, it is possible the pulley bearings are free of lubricating grease. Pressure washers produce enough force to physically push the grease out.
If it was BigBox, it is possible that Shrilly or Brob washed the machines daily.... and did a lot of damage that was unknown to anyone.
I think that inspecting the pulley bearings for ease of spin and smoothness of rotation would be a reasonable thing to do, especially after having a belt fail within minutes. Routing should be in the owners manual. Would not hurt to check the spindle bearings and ease of rotation while the belt is removed. The tension pulley should also be inspected as it could be just as clean(and rusty) as the others.
tom