“Which Face” feature causes replacement

I would like to adapt two types of face stickers to each other with the “Which Face” feature.
I set the first sticker to Which Face=0 and the second sticker to Which Face=1.
In the demo, when one person is shooting alone and another person is added, the first sticker is removed from the original person and the second sticker is applied, and the two stickers are replaced.

In the original case, the second sticker should be applied to the second person when the second person appears in the picture.

Translated with DeepL.com (free version)