Double entries in events list view #585
Description
In the commit de50b21 (v13 compatibility), the field def_lang_event_uid was added to day records.
This field seems to be used in DayRecordService->removeAllByEventUid() to decide which days are deleted when an event is changed.
The value of this field is set when manually adding a new event but NOT during import, which means that an additional day record is always created when an event is changed manually for the first time. The event then appears twice in the list view (maybe this is connected to this issue #584).
In my opinion, the importer has to be completed accordingly and an upgrade/migration task to set the value on existing day records has to be added fix the problem.