Swift Firebase Send Verification Email with apple login

When I try to send an E-Mail verification with a normal (E-Mail/Password registered user), I receive it.

When I send a verification Mail with an Apple Login registered user and he doesn't hide the email, it also works.

But when I try to send a verification Mail with an Apple Login registered user and he hides the email, I don't receive it.

I thought firebase would forward this email to the real email address??

The E-Mail I get from the user looks like this: mxrjzhdxky@privaterelay.appleid.com

My code:

Auth.auth().currentUser!.sendEmailVerification { error in
   if let error = error {
      print("Error of Verification email: \(String(describing: error.localizedDescription))")
   }
   print("Email sent")
}

I also get the "Email sent" text in the console.