Why can patching the initialization of a VOF case fail when it is using a region cell register?
The patch for VOF cases by default have the flag "Patch Reconstruct Interface" active. This setting requires that a selected register to patch is correctly defined. This means that for a region register the min-value must be smaller than the max-value for each direction. If this is not the case the patch will not change any value.
As a solution use either of the following:
a - deselect "Patch Reconstruct Interface"
b - provide a correctly defined cell register