Any reversible (by which I mean not leaking heat to outside) process should entangle the photon and the electron, leading to the consequences I described. This condition is a fairly reasonable way to read your post, but apparently not what you intended—you intended a non-reversible process, which has the consequences you describe, and explains how an apparently uninformed observer would see the interference pattern go away: the information leaked out.
Okay, after some consideration:
Any reversible (by which I mean not leaking heat to outside) process should entangle the photon and the electron, leading to the consequences I described. This condition is a fairly reasonable way to read your post, but apparently not what you intended—you intended a non-reversible process, which has the consequences you describe, and explains how an apparently uninformed observer would see the interference pattern go away: the information leaked out.