Confusing log messages when stages fail to save changes to a document

[laserval]

The log messages when a stage fails to save document changes are confusing. The message looks like this:

2014-10-08 16:28:41,304 [something] ERROR internal - Node gave an unexpected response: HTTP/1.1 404 Not Found
2014-10-08 16:28:41,336 [something] ERROR internal - Message: No document found matching your query
2014-10-08 16:28:41,336 [something] ERROR com.findwise.hydra.stage.AbstractProcessStage - Unable to persist an error to the database for doc '{"_inc":48701637,"_new":false,"_time":1412778518,"_machine":-628162613}'

There are a few confusing terms used:

• "Node" means Hydra Core
• No mention of what stage API method that was used
• "ERROR internal" sounds like and error from Hydra Core, when it actually comes from the stage