Upgrading from 4.x to 5.x inserted 12:00am end time for all events

When I upgraded to 5.0.3 from the January 4.x release all of my events with a start time had an end time of midnight added to them. I leave end times out because I don’t want to clutter my calendar with them and because they aren’t especially useful for my purpose. This is (a) kind of a dick move since I have to manually edit each event to remove the end time and (b) not even a sensible default to add when migrating data since midnight on the event date will always be before the start time unless the event starts at midnight for some reason.