Appointments created appear for a second, then disappear

Today, for some reason, when I create an appointment in the calendar, it saves ok, shows on the calendar for a second, then disappears!  Crazy.  And it never makes it to Google calendar.  I can create one on Google and it will eventually show up in EMclient.

that is indeed strange, we’ll need the logs to see what is wrong.
Go to Tools>Settings>Advanced and set up GData/Google calendar logs (depending on your version of eM Client).
Restart eM Client.
Replicate the issue with a disappearing event.
Go back to Advanced settings, click ‘Send logs’, change the recipient to and add a link to this forum topic and the name of the tested event in the body of the message.
Thank you for your cooperation.