I do not regard the Mandela / Shazaam cases as scientific evidence at all. They are about fallible human memory and possibly people being told the wrong information initially, then time passing before they realise the truth.

I give these cases the same consideration as I give to people who report sightings of UFOs and who make exotic claims. 95% of UFO sightings are subsequently explained as normal phenomena. The remaining 5% are of course unidentified, but there are numerous reasons why they are unidentified and numerous possibilities of what they may be and where they may be from. I do not believe that any of them have been created 'elsewhere'.