Sometimes Lightroom (NOT Lightroom Classic) doesn't see a face in a photo. How can I point out the (obvious) face and then be allowed to tag it?

Sometimes Lightroom (NOT Lightroom Classic) doesn't see a face in a photo. How can I point out the (obvious) face and then be allowed to tag it? Seems odd that it sometimes sees tiny faces in the background and misses obvious ones in the foreground. Sometimes it sees objects as “faces,” but then misses clear people with two eyes, a nose and a mouth. Ultimately, I would like to take these name tags and embed them in the image as metadata, but I have to get the tags on them first. Puzzled because this seems like such an obvious need, since facial recognition is never going to be 100% accurate.