The event that occurs during an outbreath, is entered through one of the three doors, involves reality strobing, etc.

Surely all the similarities with fruitions can't be coincidental and the event is caused by a similar kind of process. What exactly happens in an A&P unknowing event compared to a fruition, and what are the fundamental differences that produce the different outcomes between the two? Is it just a fruition but with some stuff still on the "self side" of awareness?

It is what it is, of course.

Thanks for raising this, I have heard it said a few times that fruition can be confused with an A&P unknowing event. Never understood this as I have not experienced them, only fruition from equanimity. I have never lost consciousness in an A&P event.

has a loss of consciousness happened to you during an A&P? 

B

What is the source for this description?

Some people, but certainly not everyone, can experience a pause, blip, glitch, gap-like thing, silence, black space, void-like depth, or something else like that at the bottom of the out breath at points during the A&P phase, as well as Dissolution, and some other transitions.

These non-Fruition but very hard to comprehend, often seemingly formless, sometimes seemingly timeless or severely time-distorted events can be confusing, particularly to people who know the maps and are wondering if they were Fruitions.

I have had numerous events like that along the way during various A&Ps, but definitely not all of them by any means, and some people never notice anything like that.

For what it's worth, Culadasa in TMI provides a seemingly satisfactory answer. According to him, cessations can can occur at any stage but their transformative power depends on the extent to which the "sub-minds" were "unified" when the event occured.

"If the mind were completely unified [during a cessation], then every sub-mind within the mind system would be affected simultaneously, and there would be a complete Awakening of the entire mind-system.
However, if the mind was only partially unified, there are two possibilities: no transformation, or incomplete transformation. [...] With too little unification, a person may have a very memorable peak experience, but with little or no lasting effect."

It is true that some people prefer much looser, less precise, more inclusive, more vague definitions, and, if those work for you, enjoy.