MapperParsingException on previously valid mapping

[kwloafman]

I'm running 1.2.1 and getting the same error without include_in_all:

curl -XPUT stealth:9200/filters?pretty
{
"error" : "MapperParsingException[mapping [pseudo_doc]]; nested: MapperParsingException[Root type mapping not empty after parsing! Remaining fields: [content : {dynamic=false, properties={content={type=string}, title={type=string}, urls={type=string}, author_name={type=string}, author_id={type=string}, destination_url={type=string}, publisher={type=string}}, type=object}]]; ",
"status" : 400
}

The only mapping is in config/mappings/_default/pseudo_doc.json:

{
    "content" : {
        "dynamic" : false,
        "type" : "object",
        "properties" : {
            "author_id" : {
                "type" : "string"
            },
            "author_name" : {
                "type" : "string"
            },
            "content" : {
                "type" : "string"
            },
            "title" : {
                "type" : "string"
            },
            "urls" : {
                "type" : "string"
            },
            "destination_url" : {
                "type" : "string"
            },
            "publisher" : {
                "type" : "string"
            }
        }
    }
}

[clintongormley]

See #6304 (comment)