Problem updating Twitter via REST PUT

It seems that when updating an existing Contact via REST PUT, a supplied value for the Twitter social account will not replace a blank entry. PUT properly adds the Twitter account when creating a new Contact, but will not update an existing Contact.

Example data to use with REST PUT:

{
  "duplicate_option": "Email",
  "email_addresses": [
    {
      "email": "dolores.diva@example.com",
      "field": "EMAIL1"
    }
  ],
  "family_name": "Diva",
  "given_name": "Dolores",
  "social_accounts": [
    {
      "name": "doloresdiva",
      "type": "Twitter"
    }
  ]
}