Turns out a user was updating documents with a new field "_index" and was causing all of the issues.
It is odd elasticsearch will allow documents to be updated with fields like _index and _id....
#mods you can remove this post
I'm getting the following error and I'm having trouble understanding how a metadata field like [_index] can have this problem and how I can fix it. I've had this problem before, but with my custom fields so I could easily change my mapping and re-ingest the data to fix the issues. I tried to edit my mapping for _index but that promptly failed as the [_index] field can not be changed...
message [failed to update mappings], failure [IllegalArgumentException[Mapper for [_index] conflicts with existing mapping in other types:
[mapper [_index] cannot be changed from type [_index] to [string]
ES version: 2.1.2
Any help would be greatly appreciated.