photos not identifying faces in Sequoia

I recently upgraded to Sequoia and my photos file of 46K photos has left 10K photos with unnamed faces. These faces were identified before I upgraded. There are several names correctly identified now in photos, but when I go into the People & Pets option and try to get it to review more photos, I get the message - there doesn't appear to be any additional photos of ...- even though there are hundreds more. I really don't want to have to manually rename each person in the 10K photos again. Is there another option?