Following @clarkej recommendation to post the potential bug here as well:
There is a behaviour which is lasting since v11 that I never reported.
When creating a new event, the end date is not saved. A page refresh is necessary to be able to enter the end date and save again properly.
No error is displayed,
can you share code or screen shot!
Sorry I don’t know what code I can share nor a screenshot.
Basically you create a new event, you enter start and end date and save. On my side the end date is not saved.
If immediately trying to enter the end date again the document will not save giving error that there are changes made to the document and you should refresher to see the new event.
After refresh you can save the end date.