deconstruction area appears to be X+1, Y+1 from construction area
I did a thing, and now it seems to be working. Not sure what is aligning to grid, but it was causing troubles

-- Align to grid

-- if W % 2 == 0 then X = X + 0.5 end
if H % 2 == 0 then Y = Y - 0.5 end

I'll be damned, this fixing the same problem i encounters as well.
Scratching my head for hours what is wrong with my signal, turns out it's some kind of bug...

Thank you so much !

Edit :
Uups too soon, it seem fixing deconstruction in one location but on another location it give different result.