I know that there have been some major upgrades to the Qt, KDE and KDE PIM packages in the past few weeks.
One of these new "features" that I just discovered in Buster is that all new events that I try to create in KOrg save as full-day events no matter what I enter. When I try to open the event to edit it, I cannot change the time fields. When I look at the underlying iCal file it produces (my Akonadi store is an iCal folder), there is all of this strange, extraneous time zone cruft that KOrg seems to be injecting into the event. Is this just a growing pain that'll auto-fix as Buster gets more KDE updates or is this a bug that I need to start picking apart in a remote hope that someone upstream will fix it?