Opening an event for editing in Gutenberg will delete the event start time

When using the Gutenberg editor to edit an existing event, this will delete the event’s start time. More specifically: the start time is being replaced/overwritten with the end time.

Interesting enough, the original (right) start time still shows up in the date-time-picker, but without explicit manual selection it won’t be saved if the event is updated, resulting in only the end time being displayed in the frontend.