Appointments + : removed appointment won't get removed in GCal


I'm using the sync between Appointments (1.9.2) and GCal in both directions. When an appointment is confirmed, it will be synced with GCal (a secondary calendar). This is working fine! But when a confirmed appointment gets removed, the entry in GCal is not removed. I have to delete it manually in GCal.
I've disabled all plugins, but no luck yet.

Support access is granted.