It happens all the time.
We don't always observe the synchronicity surrounding and engaging us all much of the time.
When we have used a psychedelic, we can observe synchronicity better.
Also, it is the process of longer term detoxification of the psychedelic.
Psychedelics, like other drugs, have a measurable half life, that is the normal length of time after which only half as much is still in the blood stream. We know about the half life of very addictive drugs, because it is a known factor in addictions, because when only half the amount of the substance is still present, the psychoactive effect, and/or pain relief effect, is massively diminished, yet there is still half the amount of the substance in the blood. For example, opium's half life is three days, but I suspect many psychedelics which are less addictive, because of causing nausea and not bringing as much pain relief, have a half life perhaps even longer than opium's.
The phenomenon is often not detected by ourselves without a psychedelic, because with the psychedelics, we witness various entities, and might be capable of realizing that such entities can potentially be in control/possession, or influencing the behaviour of, any person we happen to meet. We might be seeing the same in normal dreaming, but simply not be capable of recognizing an entity apart from anybody else. The same entities exist in our dreams, but in disguise.
Here is an experiment for testing this principle. Indigenous Australians give one another a simple rule, useful for integrating rituals made to influence our dreams. Also necessary integrating psychedelics. One rule, "go with the dream that wakes you up".
After spending a few minutes upon waking, of reflection about the dream in mind at the moment of waking, commit yourself to observing how much of the day ahead, is in accord with that dream. Do it every day. Don't try to control the process, just observe. The principle, is that what wakes your body up from sleep, will also be what has the potential to awaken your mind.
It is the most expedient integration strategy I know.
Also, the synchronicity you are describing, is just normal integration of any psychedelic, surely??? Surely the word psychedelic meaning original "mind manifest", refers to exactly that kind of integrated synchronicity.
I guess we don't always realize the fact of how powerful psychedelics can be, because of the persons using psychedelics who were adverse to integrating their psychedelic experiences into their daily lives. I guess many who use psychedelics regularly, are in a habit pattern of avoiding such integration. Because the advice for anybody who knows they don't want to integrate what they witnessed in psychedelic visions, is to use the psychedelic same again but this time within a safer set and setting. For many folk in this forum, becoming more based in western medical science, will be that safety of mindset and setting, I gather.
Yet as western medical science did not yet explain even the synchronicity of a de ja vu, the mystery remains, and scientists tend to want to keep trying find an explanation which suits the world's current stability.
a mother a daughter a lover of life, an exorcist of addictions if ere in need of the strife, and at bottom line a wife, I might well be a bore, yet have no doubt, I stand among the poor, and beg not what for, that hat hath at, nobody's mind fell too flat