Error on saving/publishing a Document - updateDocument mutation

[cusspvz]

A coworker was playing with Prime CMS for a while and noticed that one of the Content Types could be somehow corrupted. Whenever they tried to save a page with slices on it, the slices info just disappeared for no reason. We inspected the requests and found out that the updateDocument graphql mutation was returning an error.

Here's more info about that specific request:

request

{  
   "operationName":"updateDocument",
   "variables":{  
      "id":"77c83453-34a1-4884-8d97-0ffa1e35cb44",
      "data":{  
         "title":"quem",
         "description":"",
         "services":[  
            {  
               "__index":0,
               "__inputname":"883f9c5f-ea58-413c-9124-4f51e8e7b4a9",
               "bodytitle":"awetwet"
            }
         ]
      }
   },
   "query":"mutation updateDocument($id: ID!, $data: JSON, $locale: String, $releaseId: ID) {\n  updateDocument(id: $id, data: $data, locale: $locale, releaseId: $releaseId) {\n    id\n    documentId\n    schemaId\n    releaseId\n    locale\n    data\n    publishedAt\n    createdAt\n    updatedAt\n    versions {\n      id\n      publishedAt\n      createdAt\n      updatedAt\n      __typename\n    }\n    __typename\n  }\n}\n"
}

response

{  
   "errors":[  
      {  
         "message":"The loader.load() function must be called with a value,but got: undefined.",
         "locations":[  
            {  
               "line":2,
               "column":3
            }
         ],
         "path":[  
            "updateDocument"
         ],
         "extensions":{  
            "code":"INTERNAL_SERVER_ERROR"
         }
      }
   ],
   "data":null
}

Not sure tho of what was happening under the hood. Hope it helps.