Given options something like this:

{
   "publicKey":{
      "challenge":"challenge here",
      "allowCredentials":[
         {
            "id":"credential id here",
            "type":"public-key"
         }
      ],
      "timeout":60000,
      "userVerification":"preferred"
   }
}

I see frequent, but not consistent NotAllowedError: Operation failed.

Refreshing the page and trying again typically solves the issue.

Note: No problems on Desktop Safari