D4: a conditional source-contact incompatibility

This excludes the simultaneous prescription under its explicit hypotheses. An independent central source variable need not be identified with $Ph$. No universal source-extension obstruction is asserted.

If a free contraction is a bisolution, $P_{x}H=0$, its zero source contraction is compatible with that different differential identity. It does not automatically transfer to $H_F$. Applying $P$ again would involve a derivative of a delta distribution; its normalization and bundle factors are not evaluated here.

The two-variable contact $c_F\delta$ is not the three-observation scalar calibration $cr$. IX-Free-2's freedom ${\mathcal{C}}_{\mathrm{glue}}=\mathbb{R}$ supplies no map identifying these objects and cannot absorb the contact by reassignment of the common parent parameter.