I am a layman fond of browsing books in the libraries. Recently I saw the following in a book of physics which I intuitively surmise to be not quite normal (normal in the sense of well-known and undisputed by the experts in the field of science) and, lacking knowledge, would like to know whether it is indeed the case (if not, my apology for the disturbance):
"Two situations where the mechanism remains elusive are the double-slit experiment and tunnelling in solid-state physics. In both situations the apparent paradox may come from an over-simplfied description of the problem in terms of an idealized potential. For example, in the case of the double-slit experiment, an incoming electron or photon may have an electro-magnetic interaction with the electrons of the material of the double-slit and the details of this are not incorporated into the symmetry argument. A polarization of the material of the slit could indeed imply that an electron detects whether there is a second slit or otherwise, because it could lead to different induced charge distributions. In the case of electron tunnelling in solid-state physics, the electron will certainly not see a truly flat potential. These details are not necessary to describe the symmetry, but they can be essential to understanding the mechanism. The mechnism does not have to be universal and may require a case by case discussion."
The above citation is from G. Coddens, From Spinors to quantum mechanics, p.338, London, 2015.