I was having a similar issue.
After a lot of trial and error, it seems this problem is only occurring on Simulators running iOS 15.
The face landmarks request is working just fine on a physical device (iPhone 11 Pro) running iOS 15.
Simulators running iOS 14 process the request correctly as well.
I will attempt to get my hands on other physical devices running iOS 15 to test with.
I hope this helps
Any help with testing and confirming my conclusion would be appreciated.
pandraos
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