Recorder - Event not JSON serializable

[cdce8p]

Home Assistant release with the issue: 0.84.0.dev0 (2018-12-01)
Last working Home Assistant release (if known): -
Component/platform: recorder, logbook, persistent_notification, (other?)

Description of problem:
During the execution of persistent_notification.create and logbook.log with templates as message a recorder warning appears (see below).

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

sensor:
  - platform: time_date
    display_options:
      - time

automation:
  - alias: 'Demo'
    initial_state: true
    trigger:
      - platform: homeassistant
        event: start
    action:
      - service: persistent_notification.create
        data_template:
          title: 'Test {{ states("sensor.time") }}'
          message: '**Demo**: {{ states("sensor.time") }}'

Traceback (if applicable):

2018-12-01 22:54:04 WARNING (Recorder) [homeassistant.components.recorder]
  Event is not JSON serializable:
    <Event call_service[L]: domain=persistent_notification, service=create,
      service_data=title=<homeassistant.helpers.template.Template object at 0x7f4561620780>,
      message=<homeassistant.helpers.template.Template object at 0x7f4561620710>>

Additional information:
The template is first rendered during the service call execution. Since we already log the call itself, the error occurs. Might be related to #18720

[point-4ward]

Exactly the same problem here. (on 84.b0)

[BudBundi]

Same for telegramnotify

Event is not JSON serializable: <Event call_service[L]: domain=notify, service=telegramnotify,
service_data=message=<homeassistant.helpers.template.Template object at 0x6df93c10>>

and telegram_bot send_message

Event is not JSON serializable: <Event call_service[L]: domain=telegram_bot, service=send_message,
service_data=target=[708054045], message=<homeassistant.helpers.template.Template object
at 0x6f7b1a90>>

[VDRainer]

Looks like every notify component is affected.
Seeing this also on iOS and smtp messages.

[cogneato]

Also seeing this on 84.0b0 and 84.0b1

Both of these are repeated for persistent notification and service "create"

2018-12-07 12:58:46 ERROR (MainThread) [homeassistant.components.websocket_api.http.connection.140670539353224] Unable to serialize to JSON: Object of type 'Template' is not JSON serializable
{'id': 2, 'type': 'event', 'event': {'event_type': 'call_service', 'data': {'domain': 'persistent_notification', 'service': 'create', 'service_data': {'title': <homeassistant.helpers.template.Template object at 0x7ff068a50240>, 'message': <homeassistant.helpers.template.Template object at 0x7ff068a50a90>, 'notification_id': 'config_entry_discovery'}}, 'origin': 'LOCAL', 'time_fired': datetime.datetime(2018, 12, 7, 19, 58, 46, 717462, tzinfo=<UTC>), 'context': {'id': '916f3980f2bb4d23980677384e8a37ec', 'user_id': None}}}

2018-12-07 12:58:54 WARNING (Recorder) [homeassistant.components.recorder] Event is not JSON serializable: <Event call_service[L]: domain=persistent_notification, service=create, service_data=title=<homeassistant.helpers.template.Template object at 0x7ff068a50240>, message=<homeassistant.helpers.template.Template object at 0x7ff068a50a90>, notification_id=config_entry_discovery>

[aidbish]

getting the same kind of errors

2018-12-08 21:56:44 ERROR (MainThread) [homeassistant.components.websocket_api.http.connection.140627748735072] Unable to serialize to JSON: Object of type 'XiaomiGateway' is not JSON serializable

{'id': 2, 'type': 'event', 'event': {'event_type': 'call_service', 'data': {'domain': 'xiaomi_aqara', 'service': 'stop_ringtone', 'service_data': {'gw_mac': <xiaomi_gateway.XiaomiGateway object at 0x7fe725796898>}}, 'origin': 'LOCAL', 'time_fired': datetime.datetime(2018, 12, 8, 21, 56, 44, 365576, tzinfo=), 'context': {'id': '27122b8840024516a0d37ad2795825e7', 'user_id': None}}}