The paper which ftr posted above contains that text.SP) does not represent an observable phenomenon. It is a correct mathematical starting point to derive the observable superposition effect (SE) as the nonlinear square modulus of the expression for the linear superposition principle. In spite of this existing knowledge, somehow we get systematic training to accept that individual “indivisible light quanta” interfere by themselves. The phrase, “indivisible light quanta,” represents energy “hν,” a quantum cup of energy that is exchanged between quantized materials and classical waves.
The author thinks that the wave function of a single photon does not "interfere with itself". There has to be matter (photographic screen) present, so that we can observe the interference pattern.
The claim "a photon does not interfere with itself" is vague, because one cannot test the claim.
A photon does not interact with itself in empty space. That is true, but interaction is not the same process as interference.