I believe it is the interaction between linear and discrete data between the Bar and the Block plot. StepPlot by default assumes interval data, just like block plots. So thay are all consistent.
But when you change the top plot to BarChart, that becomes the primary plot, and the axis is assumed to be discrete. Then, the block plot using the same numeric data cannot draw on the discrete axis. It should, but there may be a bug.
If you use a character X varialbe on all plots like the "Window", that works . Or, if you change "Order" to character, that will work too.
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