I'm not sure this is the place to post this or not, but here it goes.

(I apologize if this information should not be made public.)

Last week I wrote the developer of Erminig (David Hautbois) to inform him of a reproducible bug. Basically, when you "Delete Only This Instance" of a repeating event in Google Calendar, that event does not get deleted in gpe-calendar. I emailed him the steps showing how to duplicate this behavior. Here's the response I got: