Appointments+ Hijacking Google Calendar

I have a significant problem with the latest version of Appointments + that I think is similar to this thread:

This morning, I re-connected the plugin to my Google Calendar with the new API instructions. I turned on Export only for the Google Calendar settings, because I wanted to test how things worked.

My appointments from Appointments+ were successfully exported, however now all of my existing appointments in Google Calendar (which were NOT made in Appointments+) have been overwritten with generic Appointments+ information. I have no idea what these appointments even were. This seems like a very serious bug.