core: Plex play_media service does not work

Home Assistant release with the issue:

version | 0.101.3

Last working Home Assistant release (if known): Unknown - I’ve never gotten it to work

Operating environment (Hass.io/Docker/Windows/etc.):

hass.io running on a pi 3b+ Integration:

https://www.home-assistant.io/integrations/plex/

Description of problem: With the updated version of the Plex integration, I can now connect to my Plex server. The plex media players show up and provide the correct information about what is playing, etc. The plex sensor also works correctly.

I’m now trying to start a playlist from the service tool. The error I get in the log is: 2019-11-09 08:56:19 DEBUG (SyncWorker_19) [homeassistant.components.plex.media_player] Using album artist because track artist was not found: Plex (Chrome)

This seems like a different response than what I should get for a playlist (not sure why it’s telling me about a specific track artist?). The service command I’m sending is in the yaml below

Problem-relevant configuration.yaml entries and (fill out even if it seems unimportant):

entity_id: media_player.plex_chrome
media_content_id: '{ "playlist_name" : "morning music", "shuffle": "1" }'
media_content_type: PLAYLIST

Note: I eliminated the escaped double quotes because those caused JSON decoder errors (the media_content_id JSON is listed first as the example - assuming the error is the first instance of the escaped double quote):

media_content_id: '{ \"playlist_name\" : \"morning music\", \"shuffle\": \"1\" }'

2019-11-09 08:38:35 ERROR (MainThread) [homeassistant.components.websocket_api.http.connection.1916672816] Expecting property name enclosed in double quotes: line 1 column 3 (char 2)
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/websocket_api/commands.py", line 133, in handle_call_service
    connection.context(msg),
  File "/usr/src/homeassistant/homeassistant/core.py", line 1236, in async_call
    await asyncio.shield(self._execute_service(handler, service_call))
  File "/usr/src/homeassistant/homeassistant/core.py", line 1261, in _execute_service
    await handler.func(service_call)
  File "/usr/src/homeassistant/homeassistant/helpers/entity_component.py", line 213, in handle_service
    self._platforms.values(), func, call, service_name, required_features
  File "/usr/src/homeassistant/homeassistant/helpers/service.py", line 348, in entity_service_call
    future.result()  # pop exception if have
  File "/usr/src/homeassistant/homeassistant/helpers/service.py", line 372, in _handle_service_platform_call
    await func(entity, data)
  File "/usr/local/lib/python3.7/concurrent/futures/thread.py", line 57, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/src/homeassistant/homeassistant/components/plex/media_player.py", line 594, in play_media
    src = json.loads(media_id)
  File "/usr/local/lib/python3.7/json/__init__.py", line 348, in loads
    return _default_decoder.decode(s)
  File "/usr/local/lib/python3.7/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/local/lib/python3.7/json/decoder.py", line 353, in raw_decode
    obj, end = self.scan_once(s, idx)
json.decoder.JSONDecodeError: Expecting property name enclosed in double quotes: line 1 column 3 (char 2)

Traceback (if applicable):

Not applicable

Additional information: I checked in the Plex logs (which are really hard to read), and it does something - I just can’t figure out what it is doing…