When I delete a photo from “featured photos,” the rest all disappear. Is there any way to stop this?

Every so often, when I open up my ‘For You’ section on my phone’s photos, I notice some old unwanted pictures on my ‘Featured Photos’ section. Usually they’re mixed in with random photos — most I want to keep, some I want to get rid of. So I’ll go to the delete button on ONLY a single photo, not the whole album. When I tap it, all of the pictures vanish, save for one (often times it’s the same picture that stays).

Is it deleting all of the photos? Where do these pictures go if they are deleted — some of them I don’t want deleted! But if they aren’t deleted — why do they disappear from Featured Photos?

In the above photo I just blurred out my location and some faces. I had only deleted one picture but only one remains. There should be more pictures there of my dog.