There were 2 recent merges of John Lewis profile is the only thing that I can see. Possibly, Don did the merges in one 'browser window', but in a 'different browser window' with one of the merged away profiles, he was trying to add the child Ada. Other possibility was he was trying to add one of the merged away Wikitree IDs as father to Ada.
It probably is related to the merges that were done earlier today.