Photos keeps incorrectly merging the same people in faces

Number:rdar://38136012 Date Originated:2018-03-05
Status:Open Resolved:
Product:Photos Product Version:iOS 11.2.6, iPhone 7+
Classification:Bug Reproducible:Yes
The Faces feature in Photos keeps merging people, although the same fotos have been selected multiple times to be not part of that person and collected under a different name.

Steps to Reproduce:
1. Take >1000 fotos of myself (male, short dark hair, glasses), >300 pictures of my son (either no hair or very thin blond hair) and >100 pictures of my mother (long, white hair), let Photos decide they are the same person.

2. carefully select all pictures which don't show me and select "Not This Person". Pictures are removed from my faces set.

3. Go to one of the pictures of my son, name the person correctly, repeat multiple times until close to 300 pictures are correctly associated to that person.

4. Fav that person, for good measure.

5. repeat step 3 and 4, replace "son" with "mother" and 300 with 100.

6. Happily switch off phone while being charged.

7. five minutes later, switch phone back on.

Expected Results:
Each person is still correctly called in faces, no pictures have been removed from each set, especially as most of these pictures have been associated to a name by hand and have been disassociated from another name by hand, as well.

Actual Results:
1. The faces sets of both my son and my mother have vanished, instead exactly the same pictures are associated with me again.

2. repeat above Steps 1-7 multiple times, with exactly the same results.

3. Start to get angry.

iOS 11.2.6, iPhone 7+

iCloud Photo Library switched on, 2TB paid Account, around 40000 pictures in said account, Optimise iPhone Storage switched on


Please note: Reports posted here will not necessarily be seen by Apple. All problems should be submitted at before they are posted here. Please only post information for Radars that you have filed yourself, and please do not include Apple confidential information in your posts. Thank you!