Filebeat harvesters don't restart after stopping due to ignore_older

Ok just spotted this one:

And it seems that my expectation is correct and the harvester should restart.

Is this a bug or a misconfiguration on my part - I wondered if it was a corner case due to the file being empty when it is ignored :s

My configuration is really simple

---
filebeat:
  prospectors:
  - paths:
    - "/var/log/nginx/*access.log"
    document_type: nginx_access

I am using a config_dir to define prospectors in separate files.

This is my main config (comments removed for brevity) - it's mostly defaults

filebeat:
  prospectors:
    -
      type: stdin
      paths:
        - "-"

  registry_file: /var/lib/filebeat/registry
  config_dir: /etc/filebeat/conf.d

output:
  logstash:
    hosts: ["logstash.myserver.com:5044"]

shipper:

logging:
  files:
    rotateeverybytes: 10485760 # = 10MB

The weirdest thing is the stdin prospector - this is because I use Chef to add prospector files and initially there are no prospectors - Filebeat doesn't like it when you try to start it with no prospectors (I will raise this as a separate issue)

Oh, and the other prospectors are defined thus:

---
filebeat:
  prospectors:
  - paths:
    - "/var/log/nginx/*error.log"
    document_type: nginx_error
---
filebeat:
  prospectors:
  - paths:
    - "/var/log/syslog"
    document_type: syslog