If a wall is less than six feet (or 2000mm, no not exactly equal to six feet) it will NOT use the Cut line weight, it will only show using the Projection line weight. You can "force" Revit to show it as Cut by setting the Top Constraint to the level above and using a negative Top Offset value to drop it back down to it's intended overall height. A bit obtuse but it works!
I posted this because it came up in a session at RTC (during Harlan Brumm's Troubleshooting class) and then was tweeted.
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