After reading The Revit Clinic post about Plan Regions Wall Cleanups, I was reminded of a similar problem I had with Plan Regions and Wall Hatching. I had a problem where the hatching would disappear from a particular wall. I had figured out that it was related to the Plan Regions, because if I deleted the Regions, the hatching would show.
The fix posted by Ryan Duell today actually fixed my problem as well. After I set each Plan Region’s Cut Plane to match the host view Cut Plane – the hatching showed correctly! Before and after images are below.
Adjusted Plan Region Cut Plane to match host view Cut Plane: