For some blade geometries (blades with cut off), when generating the O-grid mesh, one side of the O-Grid is folded inside the blade profile, while the other side is OK
There is a bug when generating the O-grid for a blade which the suction and pressure sides are not parallel.
Make the O-grid bigger or
Move the outlet block closer to the blade trailing edge.
ANSYS CFX Release 11.0 Update 1.