This line of thinking actually jibes quite well with the other hot topic re APP: the mod that has shown up on social media (e.g., Federico Viticci, Macrumors, Reddit) of placing a memory foam insert between the earcup and stem to create a better fit/seal. If there is an issue,I suspect it may that the adhesion power of the tips degrades after several weeks' use leading to the seal not staying put. I know that has definitely occurred for me. I am constantly having to push the APP back into my ear (frequently leading to hanging up on people I’m on the phone with).
Worth noting with this line of though that APP owners with Apple Care+ are now receiving replacement tips at no cost.
Seems fairly obvious now there is some type of compositional issue with the silicon. I see the connector is slightly out of round, Im curious if this creates some issue as the tip is compressed in the ear for a week or two? I'm not an engineer but there is definitely a sealing issue at the foundation of all of theses complaints with ANC.
I'm still of the opinion the screen over the inner microphone needs a redesign.