I agree. It would seem that the cpufan1 has failed.
If you are still under warranty, I think I would try to rma the motherboard.
Otherwise, since fan2 seems to work ok, I see nothing wrong with continuing.
The presence of fan2 is a bit of news to me, but I think it is a nice feature to accomodate those cpu coolers with a push/pull dual fan configuration. A motherboard will not normally start if there is nothing attached to a cpu fan header.