Yes. I want to send a photon which we consider to be in a mixed state through a polarizer rigged to detect torque. Subjecting a photon to a polarizer is of course a measurement, but the presence of torque implies that a pure state existed prior to such measurement...unless you disagree on this point, perhaps? It's difficult for me to see an argument against it. The only way Copenhagen and MWI would plausibly predict torque is if they considered the emitter to be part of the wavefunction, as you mentioned, or if they abandon conservation of momentum. If the former, then the wavefunction never has a physical manifestation because the future act of measurement makes the photon have a pure state at the time of emission which, ironically, contradicts the basic premises of these interpretations.