Predestination paradox. In fact the entire thing is likely a predestinaiton paradox. “Activated 120 years ago”, which is caused by the imager at “now”; the reason why the two can go back home is because Tendi told them about the version according to Orion and mentioned her great-grandma being the discoverer, which is what let the past Orion to recognize the truth and probably themselves assigned it to Tendi’s great-grandma?