Two photons interfering is just two photons interfering; that's not measurement. More precisely, the wavelike photon, which is the "cause" of the interference p

Two photons interfering is just two photons interfering; that's not measurement. More precisely, the wavelike photon, which is the "cause" of the interference pattern, hits a component of a photodetector, which generates a voltage and sends an electron current through a cable, that feeds into a computer which is running a program that displays photon counts. On the other hand, if you isolate parts of the setup, for example if the interference pattern of the photon hits just a very thin slice of photosensitive material that would otherwise be part of the photodetector, I'm sure you may very well observe an electron interference pattern, for example (and a non-rigorous one, at that). In "real life" (meaning in the laboratory), measurement isn't some discrete process that can be isolated at a specific point in an experimental setup. Otherwise, there would be much better explanations for measurement in undergraduate physics curriculums. In fact, even in top physics curriculums, the problem of measurement is barely treated at all, since the interpretation of measurement in quantum mechanics is a "philosophical" problem that apparently has no place in real physics, which instead must concern itself with mathematics that is phenomenologically accurate.