Class 3 Error
When using a regular hexahedral grid, or something similar, it is possible for a Plane created at constant X, Y or Z to exactly coincide with faces of elements, especially at boundaries of domains or subdomains. In these circumstances, CFX-Post may fail to locate some of the points on the plane and graphics would show uncoloured regions around these points. Moreover, quantitative analysis on these planes (e.g. area averages) would then be incorrect.
There is a problem in the way that CFX-Post searches for point
If possible, move the plane slightly away from element boundaries.
ANSYS CFX Release 12.0.