My post-registration webhook returns

{"identity":{"metadata_admin":{"groups":[{"id":1,"role":"user"}]}}}

(verified it) with correct headers and Kratos debug logs says "ExecutePostRegistrationPrePersistHook completed successfully.". According to the docs (link) Kratos should update the admin metadata of this user, but the content doesn't change – and no errors in the logs. How to best debug this? 🙏 I already have logs set to debug but I can't see any issues.