There's a technical term for the visual alternation phenomenon -
binocular rivalry - so it's nothing new. I myself noticed it happening for the first time while on mushrooms nearly 3 decades ago. I'd say the fact that you've noticed it is an effect of the general amplification of awareness that psychedelics can produce. Hence, you've simply become aware of something that was previously a background process which you were hitherto, well, not even taking for granted.
An integration break will be a great time for carrying these insights further, bringing non-drug techniques to the table, and generally taking good care of yourself through diet, exercise, self-education, creative endeavor, and contact with outdoor nature.
This could be the tip of the iceberg - consider how you can optimise the experience of the world for not only yourself but others around you. In a sense, the visual alternation phenomenon could be seen as a metaphor for how one might choose one's perspective in any given situation.
PS - remember, the brain is an exquisitely adaptive organ regardless of what your ego structures might have to say about this! What makes you so sure it was operating in a "natural" way in the first place?
βThere is a way of manipulating matter and energy so as to produce what modern scientists call 'a field of force'. The field acts on the observer and puts him in a privileged position vis-à-vis the universe. From this position he has access to the realities which are ordinarily hidden from us by time and space, matter and energy. This is what we call the Great Work."
β Jacques Bergier, quoting Fulcanelli