Instead, no dancers change positions at all, and nothing happens.
It's true that the call isn't legal from this position. A gripe would be nice, though I understand that code clutter to catch cases like these won't be a priority...
CSDS allows more than one call to be given on a single line.
On line 3, it executed the call 'Zig-Zag' followed by the call 'Zig-Zag'. Executing Zig-Zag twice from a R-H Box ends all dancers in the same position!