Remark: Two necessary scope qualifications

The proposition concerns the retained responses, not every auxiliary object written in this file. The vertex is quadratic, the one-contraction verification contains a cubic pointwise term, the commutator is a scalar multiple of the identity, and the finite instruments are channels, not degree-one field elements.

Also, applying the unweighted formula to the background-dependent $c_2[h,k]$ would produce degree-three $h$-terms and mixed $hk$-terms. Such a substitution is not in the degree bound of Proposition prop:scope and contributes only at physical order ${\kappa }^3$ after the extra vertex factor. No universal degree-two bound for arbitrary compositions is claimed.