Configuring mysensors to use a json format persistence_file with the mqtt gateway results in an error

**EDIT - This has been resolved, these are non-blocking errors and if let to do its own thing HA will write the file and all is well.

Good evening,

I have this working well all sensors report and trigger as expected, but one thing I wanted to change was the persistence_file to json format instead of the default pickle for easier editing.

So I edited my configuration.yaml to look like this:

    - device: mqtt
      persistence_file: '/home/homeassistant/.homeassistant/mysensors.json'
      topic_in_prefix: 'gateway-01-out'
      topic_out_prefix: 'gateway-01-in'
  optimistic: false
  persistence: true
  retain: true
  version: '2.0'

However it seems no matter the path chosen the following errors occur:
2017-12-28 18:40:52 ERROR (MainThread) [homeassistant.config] Invalid config for [mysensors]: /home/homeassistant/.homeassistant directory does not exist or is not writetable for dictionary value @ data[‘mysensors’][‘gateways’][0][‘persistence_file’]. Got ‘/home/homeassistant/.homeassistant/mysensors.json’. (See /home/homeassistant/.homeassistant/./configuration.yaml, line 606). Please check the docs at
2017-12-28 18:40:52 ERROR (MainThread) [homeassistant.setup] Setup failed for mysensors: Invalid config.

If I remove the persistence_file line from the config, the system loads fine, and stores the sensors in the pickle format.

I’ve verified the permissions, as this is the same folder the rest of the Home Assistant config is stored in, along with the pickle format file.

ls -lad /home/homeassistant/.homeassistant 
drwxr-xr-x 5 homeassistant homeassistant 4096 Dec 28 18:45 /home/homeassistant/.homeassistant
-rw-r--r-- 1 homeassistant homeassistant 319 Dec 28 18:18 /home/homeassistant/.homeassistant/mysensors1.pickle

Any suggestions are welcomed, I’ve been losing my mind on this.

Thank you.