The Epidemic of Amnesia.

[Iscah]

With Elidibus even if he chose to look at the memories tied to his convocation stone we know that they 100% wouldn't have been his own. But mostly memories Lahabreha and Emet-Selch had of him.

For the sundered-and-reinstated Ascians this is generally the case, but Elidibus is more complicated.

On the one side, he's one of the people who created the memory stones in the first place, so he had the opportunity to insert his first-hand memories rather than just what others thought of him.

On the other, he was by that point not actually himself but a primal who may or may not have had Themis's soul within it, so there may have been some benefit in the other two adding their memories of the original person. But even without that, the memory stone should have helped "reset" primal-Elidibus's memory to everything he had of himself at the time of creating the stones and which has since been lost.