_termvector returns JsonGenerationException if called between index and refresh

[brwe]

To reproduce:

DELETE testidx

PUT testidx
{
  "settings": {
    "index.translog.disable_flush": true,
    "index.number_of_shards": 1,
    "refresh_interval": "1h"
  },
  "mappings": {
    "doc": {
      "properties": {
        "text": {
          "type": "string",
          "term_vector": "with_positions_offsets"
        }
      }
    }
  }
}
POST testidx/doc/1
{
  "text": "foo bar"
}

GET testidx/doc/1/_termvector

results in

{
   "error": "JsonGenerationException[Current context not an object but ROOT]",
   "status": 500
}

A more meaningful error message maybe?