Google Calendar Missing Events Rated 5 out of 5 stars
To all those users whose Google calendar events are missing since upgrading to TB15 and are using Lightning 1.7 or below, upgrade to "Provider for Google Calendar 0.16" https://addons.mozilla.org/en-US/thunderbird/addon/provider-for-google-calendar/
I have 7 individual calendars using Provider for Google Calendar (not CalDav) for the api. No events were showing for any of those calendars. Upgrading Provider for Google Calendar to version 0.16 from 0.13 restored all my events back to normal.