Well well well, look who decided to update their API (Google did).

Update functions that call events.watch, events.list, along with any tests and utils. This is to remain up-to-date with the lates Google Calendar API changes. See below for all details:

We are writing to inform you about upcoming changes to the Google Calendar API v3 that may impact your applications and notification handling, starting March 11, 2024.

What does this mean for your organization?
The Google Calendar API v3 will now include the eventType parameter to subscribe to specific event types when using Events.Watch. Additionally, starting March 11, 2024, the following changes will be introduced:

Default event type filters alignment for both Events.list and Events.watch.
Error handling for operations not supported for special event types, such as WorkingLocation, Out of Office, and FocusTime events.
What do you need to do?
To prevent any direct impact in your applications, we strongly encourage you to review your usage of the applications listed below and take the following actions:

Events.watch: Specify the event types you need for your application as a parameter to reduce your infrastructure costs. In case you want to request a quota increase, please make sure you have implemented event type filters appropriately. This factor will be considered when we are evaluating quota increase requests.
Events.list: Specify the event types you need for your application as a parameter. Without making this change, working location events will start to be returned.
Event type: If your code is performing operations on special events, it is important to review it to ensure that your code does not attempt to perform operations not supported for special event types.
We’re here to help
Explore the updated documentation and resources to learn more about Google Calendar API v3:

Manage focus time, out of office, and working location events documentation
Manage quotas
If you have additional questions, please refer to get help from Google and the developer community.

Thanks for choosing Google Workspace.

– The Google Developer Team