Upon install I would get this error in my logs.
Warning: session_id(): Cannot change session id when headers already sent in Symfony\Component\HttpFoundation\Session\Storage\Proxy\AbstractProxy->setId() (line 94 of drupal/vendor/symfony/http-foundation/Session/Storage/Proxy/AbstractProxy.php) #0 drupal/html/core/includes/bootstrap.inc(600): _drupal_error_handler_real(2, 'session_id(): C...', '/var/aegir/plat...', 94, Array)
#10 drupal/html/modules/contrib/google_calendar_service/google_calendar_service.module(108): Drupal\Core\TempStore\PrivateTempStore->set('calendarId', 'all')
#11 [internal function]: google_calendar_service_views_pre_view(Object(Drupal\views\ViewExecutable), 'block_1', Array)
Closed: cannot reproduce
2.0
Code
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
I wasn't able to replicate this, have you tried with the latest version:
https://www.drupal.org/project/google_calendar_service/releases/8.x-2.x-dev →
I couldn't reproduce it so I'll close it.