Hello,
I have recently came across a problem with a hatch. Take a look, the upper one it is an AutoCAD style (found at a site with free styles) imported directly to a Rhino project and the scaling is valid, each wall segment has its own settings. The bottom one is another hatch, with the same settings, but in this case everything seems to be all right.
Can you send me the model with the hatch pattern and the 3 walls?
My guess is that the section pattern on the wall of the right has reached the maximum number of hatch lines, which VisualARQ currently sets at 100.000 lines per hatch. We use this limit to avoid extremely slow sections on very dense hatches. Rhino 6 has a limit of 160.000 lines per hatch.