face recognition not propoerly converted from Elements 13 to 14

Elements 14 has converted my catalogue from Elements 13. Working myself through the catalogue I come across hundreds of pictures that I tagged in Elements 13 but the faces are not properly recognized in 14.
One picture has two faces, the tags show two persons but if I go over the faces only one face is recognized and the other is not. I have to manually mark the other face.
I rather would like to say Elements do the face recognition for this picture again but I cannot.

(This problem might be a side effect of the other problem I reported that multiple faces within a picture are not properly recognized).