When new user register, but doesn't upload his custom avatar (and he doesn't chose it from default avatarts), he will get GOAL aout avatar uploading. But he should not.

From what I checked, it seems like you have configured a default user avatar image from your profile type, this is why system detected this user account already has avatar image after they done the registration. https://take.ms/ju1iJ

Because that social goal for "update your avatar" section as long as user has any avatar or default avatar, it will treat it as user already has updated their avatar.

Unless, you remove your default avatar configuration from your profile type.