thats about right actually.
the VRMs get a LOT hotter than people realize. when i was overvolting my 5870 my VRMs were nearing 120c.
that one VRM probably just doesn't have optimal contact with the thermal tape. if it bothers you, you can apply some TIM or just try reseating the HS.
they are designed to run at those extremes though, so they should be fine.