Copy_to doesn't show up search using _all

Elastic Stack Elasticsearch
1

I'm using ElasticSearch v1.6, and running on t2.medium AWS EC2.

Here is my simple mapping

PUT /my_index/_mapping/contact
{
"contact": {
"dynamic" : "strict",
"index_analyzer": "index_analyzer",
"properties": {
"name": {
"type": "string",
"copy_to": "orig"
},
"title": {
"type": "string",
"copy_to": "orig"
},
"orig": {
"type": "string",
"index_analyzer": "index_orig_analyzer",
"include_in_all": true
}
}
}
}

I won't be able to search out values in orig using the following search query. But if I change from "_all" to "orig" it will work.

GET /my_index/contact/_search
{
"query": {
"match": {
"_all": "test"
}
}
}

Any idea why it's like this?
Thanks