Williams-R-causes-backtest-to-hit-Execute-Error

I dropped a SmoothInd(Wm%R,DEMA) into a condition block of a functional strategy and got an "No Execution" notification on the status bar.

I pushed the BuildingBlock Strategy to C# code and tried running it for the "compiler messages". It looks like the abreviation for Williams %R (Wm%R) is causing the issue.

If I switch Wm%R for WilliamsPctR the strategy runs....