Strange behavior when displaying a sensor in a group

I added a calendar to my HA install and when looking at the states page the next event is correctlt showing in the attributes for the calendar.

Next I wanted to display the next upcoming event on my main view so I created a sensor with that information and put it in its own group and put that group in my main tab which is set to (default_view).

What is strange is that every time I restart HA the group containing that sensor isn’t displayed anywhere. But when I go to the configuration page and “reload groups” then suddenly it shows back up again.

Here is the code for the sensor and the groups:

- platform: template
  sensors:
    next_event_template:
      friendly_name: "Next Event"
      value_template: "{{ (states.calendar.<my_calendar>.attributes.message) }} on {{  as_timestamp(states.calendar.<my_calendar>.attributes.start_time) | timestamp_custom('%-m-%-d-%Y @ %H:%M') }}"

calendar:
  name: Calendar
  entities:
    - sensor.next_event_template

default_view:
  view: yes
  name: Main
  entities:
    #- updater.updater
    - group.calendar
    - binary_sensor.ha_update_avail_template
    - binary_sensor.haapi_mqtt_test
    - group.alarm_panel
    - group.mbr
    - group.sunroom
    - group.basement
    - group.garage
    - group.lights
    - group.switches
    - group.cameras
    - group.devices

As a work around I can always set up an automation to reload my groups after a HA restart but that doesn’t sound like the proper way to do it. I can’t figure out why it won’t display correctly just like the rest of the groups do.