Version: 50.0.2661.32 (Official Build) dev (64-bit)
OS: Chrome OS 7978.18.0 (Official Build) dev-channel samus

After power-washing my Chromebook and logging back into my accounts the configured wallpapers have yet to be synced even though from chrome://sync-internals it appears to know which wallpaper it should be using:

{
  "ATTACHMENT_METADATA": "",
  "BASE_SERVER_SPECIFICS": {},
  "BASE_VERSION": "1456786261271813",
  "CTIME": "Thursday, June 12, 2014 at 11:50:42 PM",
  "DIRTY_SYNC": false,
  "ID": "<redacted>",
  "IS_DEL": false,
  "IS_DIR": false,
  "IS_UNAPPLIED_UPDATE": false,
  "IS_UNSYNCED": false,
  "LOCAL_EXTERNAL_ID": "0",
  "META_HANDLE": "3439",
  "MTIME": "Tuesday, January 5, 2016 at 9:59:26 AM",
  "NON_UNIQUE_NAME": "wallpaper-sync-info-key",
  "PARENT_ID": "",
  "SERVER_ATTACHMENT_METADATA": "",
  "SERVER_CTIME": "Thursday, June 12, 2014 at 11:50:42 PM",
  "SERVER_IS_DEL": false,
  "SERVER_IS_DIR": false,
  "SERVER_MTIME": "Monday, February 29, 2016 at 2:51:01 PM",
  "SERVER_NON_UNIQUE_NAME": "wallpaper-sync-info-key",
  "SERVER_PARENT_ID": "",
  "SERVER_SPECIFICS": {
    "app_setting": {
      "extension_setting": {
        "extension_id": "obklkkbkpaoaejdabbfldmcfplpdgolj",
        "key": "wallpaper-sync-info-key",
        "value": "{\"appName\":\"\",\"layout\":\"CENTER_CROPPED\",\"source\":\"ONLINE\",\"url\":\"https://storage.googleapis.com/chromeos-wallpaper-public/20140527-164513_earth-009_high_resolution.jpg\"}"
      }
    }
  },
  "SERVER_UNIQUE_POSITION": "INVALID[]",
  "SERVER_VERSION": "1456786261271813",
  "SPECIFICS": {
    "app_setting": {
      "extension_setting": {
        "extension_id": "obklkkbkpaoaejdabbfldmcfplpdgolj",
        "key": "wallpaper-sync-info-key",
        "value": "{\"appName\":\"\",\"layout\":\"CENTER_CROPPED\",\"source\":\"ONLINE\",\"url\":\"https://storage.googleapis.com/chromeos-wallpaper-public/20140527-164513_earth-009_high_resolution.jpg\"}"
      }
    }
  },
  "SYNCING": false,
  "TRANSACTION_VERSION": "2",
  "UNIQUE_BOOKMARK_TAG": "",
  "UNIQUE_CLIENT_TAG": "<redacted>",
  "UNIQUE_POSITION": "INVALID[]",
  "UNIQUE_SERVER_TAG": "",
  "isDirty": false,
  "modelType": "App settings"
}