Clean OS / KDE apps install, added new 'Google Calendar and Tasks'. supplied login info and 2FA code and calendar was populated. Reminders of historical events immediately flooded a Korganiser notifications window. In the background, email reminders (most events had an email reminder configured) were being sent - totally unbeknownst to me until the 501st triggered ISPs SMTP relay lockdown. At which point I was bombarded with email failure system-tray notifications too. Additions of new events with an emailed notification set are (correctly - as per bugfix https://bugs.kde.org/show_bug.cgi?id=318392) not sent.
No worries. I'm simply moving these from the korgac product to korganizer::reminder . sorry for the noise but I want to have all the reminder bugs located in the same place.