If we once start with that the code will be a real mess some day, and we’ve avoided it for 4 years now. It’s also not unlikely that Samsung fixes bugs in the SPlanner - they have done it several times and thats why it is used by the people instead of Googles own base Calendar app.
@esprit-libre Thunderbird probably doesn’t use the same REPORT calendar-query request, so that the server error (which occurs when the server tries to process the events in order to process the REPORT calendar-query request) doesn’t occur.
You can create a new calendar, upload a single event, and then have a look whether the problem occurs. If it does, you have a look at the uploaded event, and the current event in the server’s database.
However, it’s clearly a server problem, so I suggest to report it to the server vendor and continue discussion there. Which server do you use?
BTW: Android doesn’t support events without end dates. All-day events will become assigned end := start + 1 day, the other events end := start.
