New Kubota bx25 vibrate

[Canam]

I just get my new kubota bx 25 over the weekend and when the tractor is leaning to the left about 8 inches lower then the right I can feel a vibration Like something is rubbing while moving and stoped. I leaned it to the right and was fine. Called dealer and someone is coming to look at it soon. Any ideas what it could be ? Thanks