I've seem the same thing in some pictures-- I've been adding them to a "Weird No Name" album to keep track of them and to see if anything changes. There's one set that has refused to use a Key Photo, and just puts initials. Another set, like yours, just doesn't show a name at all for someone that is clearly named.
I've fooled around with them some, changing the key photo, changing the name, rebuilding the library, etc. Some of the initialed names have come back, though not on my phone. But I think that the "no name on pictures" ones have not changed.
If I scroll to get to "explore" section, and I click on the picture, it takes me to the correct People album. So the database seems OK.
So you're not alone. I have yet to upgrade to OS26-- I hope that works…