SUMMARY
Korganizer still shows holidays from the Google calendar, even when they've been de-selected in the calendar configuration

STEPS TO REPRODUCE
1. Associate Google Calendar with Korganizer
2. Settings->Configure Korganizer->General->Calendars
3. Select Google Calendar, click "modify"
4. Un-select "Holidays in United Kingdom" (my location, I assume others have something similar).
5. Click OK

OBSERVED RESULT
On Clicking OK, I see messages to say the calendar's syncing. These mention UK holidays. Click OK to close dialogue, and holidays are still showing in the calendar.

EXPECTED RESULT
Holidays should not be shown in the calendar.

SOFTWARE VERSIONS
(available in About System)
KDE Plasma Version: 5.13.5
KDE Frameworks Version: 5.50.0
Qt Version: 5.11.1

ADDITIONAL INFORMATION
I have deleted all default calendars, so the Google calendar is the *only* one in use, so I can be sure this is the one from which holiday data are appearing. I've also confirmed this as the source by logging into calendar.google.com and temporarily enabling holidays there - the same ones appear.

Not a major bug, more a "would be nice to get rid of" bug.
Thanks