Something strange happened in this case. I guess that while most clients only have one field for "Display Name," Primal and noStrudel have an additional field for Username, too.

So, while nostr:nprofile1qy2hwumn8ghj7mn0wd68ytn00p68ytnyv4mz7qg4waehxw309aex2mrp0yhxgctdw4eju6t09uq3wamnwvaz7tmjv4kxz7fwwpexjmtpdshxuet59uqs7amnwvaz7t6qdehhxtnvdakz7qgswaehxw309asjumn0wvhxcmmv9uq3camnwvaz7tmrdpexjum5wp5kcmpwdehhxarjxyhxxmmd9uq3zamnwvaz7te3xsczue3h0ghxjme0qys8wumn8ghj7cmgdae82uewd45kketyd9kxwetj9e3k7mf6xs6rgtcpr9mhxue69uhkxmmzwfskvatdvyhxxmmd9aex2mrp0yq3samnwvaz7tmrv4kxcctj9ehx7um5wgh8w6twv5hsqgzu2pnpkzfvc7rt2h9466g5nvffhhxgupwhywxvv577nar9a45ljygugx4k had updated his Display Name in another client, this did not update the Username in Primal and noStrudel, and the Username overrides the Display Name in those clients.

For the life of me, I don't know why they have both, or why updating the kind 0 in a client that doesn't have that tag at all didn't wipe it from Primal and noStrudel. Unless they save that particular datapoint in a separate note from the kind 0, maybe?