Calendar Entity no Attributes

I’ve been using a Google Calendar entity for years but recently it’s stopped working and I can’t figure out why.

I can see the calendar in the UI under (sidebar → Calendar), I see the entry and all the details, but I don’t see anything under the attributes when I search for that calendar entity under development tools. Instead, all I get is:

offset_reached: false
friendly_name: Training Peaks Cal

For years I’ve been accessing the details in a template sensor like this:

{% set description = states.calendar.tp_training.attributes.description %}

What’s going on?

It has been recommended practice for more than 4 years to use the state functions in templates, not the state-object method: {% set description = state_attr('calendar.tp_training','description') %}

Are there any errors in the logs?