How commonly are instances of people experiencing the “Mandela Effect” as well as feelings of Déjà vu, a consequence of do-over periods of time orchestrated by the Extraterrestrial Alliance to remake history in some respect?

This is definitely the explanation for instances of the so-called Mandela effect where people have recallable memory from having lived to witness large-scale events, such as that African civil rights leader being assassinated, whereas history and the memories of most human beings never witnessed such an event. Those eyewitnesses happen to have a recallable memory of the previous timeline that was truncated by an extraterrestrial time travel maneuver to repeat that period of history, and a divine intervention was able to deflect the energies in a way that spared his life. The extraterrestrials saw that as a technical error that was somewhat mysterious but was left in place because it was not that high a priority to ensure his demise. The experiencing of déjà vu approximately half the time is due to a time travel do-over arranged by the Extraterrestrial Alliance. The other instances are due to having precognitive awareness of what is coming in the future and hence, this creates a feeling of familiarity when the events actually occur in the present moment being experienced.