The new “pet detection” feature in Photos on macOS is doing some weird stuff. It put photos of my dog into two different collections in the “People and Pets” section.

When it does this with people, I can drag one collection onto the other to merge them. But with these two collections of my pet, it doesn’t allow the merge. The drag target doesn’t even “activate” (a slight grow animation) to indicate that it can accept the drop.

As usual, no error message or explanation in the app.