Missing search results with the explore function via face recognition.

Hi there,

I'm not sure why, but when I try to find pictures of a person using the explore function, only a few pictures are displayed. However, if I select a picture that shows the person but is not listed via the explore function, the person is recognized correctly.
It almost seems as if some kind of filter function has been activated. But I could not find any.
Does anyone know this behavior?