Strange behaviour with Nurbs curve PWK and Merge

[brt1]

I reconstructed an ellipse to a special shape by moving its control points and creating a new “Nurbs curve PWK”.
The second step is to alter two control point weights with sliders which i plugged into position 1 and 4 of a merge component. When checking the output of the merge, the values appear on position 0 and 1 of the list.
Additionally both of the altered values influence the same CV (1).

Is this a bug in the merge component or am I using it wrongly?

curvePWK_merge.gh (37.9 KB)

[inno]

if you remove the Flatten and check the Data Tree output by the Merge component:

Flattening just removes the Branches, and that order is maintained:

easiest solution is to flatten this:

safest solution is to flatten all inputs of the Merge:

[brt1]

hi inno,
thanks a lot for the quick help and comprehensive explanation on this late evening beginner´s mistake