Exchange of spreads

I have a problem, that I don’t know if it is a defect or mistake something me.
using the module contour and getslice(spreads) or stallone(spreads) when two objects are lined up in horizontal, the values of the spreads 1 pass to 2 and those of 2 they pass to 1.
I attach a patch of example.
thanks to everybody.

prova1.v4p (11.2 kB)