Problems with setting up of recurring tasks in KOrganizer 5.3

hi all,

there seems to be some strange behavior in KOrganizer when setting up recurring tasks. 
Before writing a bug ticket, I'd like to check if the issue is already known (or if I'm doing 
something wrong).

My setup:
KOrganizer 5.3
KDE Applications 16.08.2
OpenSUSE leap 42.2

When setting up a non-recurring to-do, everything seems to work as expected - I can set 
start dates, due dates and reminders without the different settings influencing each other.
However if the to-do is set to recurring, response to the settings is erratic.
An example:
     *  I set up a to-do, starting the next day (at a specific time), and due one day later. A 
reminder is set at 15min before due time.
     *  the to-do is shown correctly in the to-do list view, and also more detailed via the 'show' 
context menu entry
     *  when I add a weekly recurrence, start and due dates are mysteriously moved by two 
days in the to-do list view, while via the 'show' context menu only the due date is shifted, 
and only by one day..
In other cases I've also seen the reminder being changed in addition, recurrence setting 
being greyed out, or also an error messages when trying to save the modified task 
(something like 'only allocated resources are allowed to make changes', I can't reproduce 
this right now). 

The behavior does seem independent of the calendar type I select - local personal 
calendar vs. CalDAV

(In the case of a local calendar, I tried to look at the .ics file. However that's confusing as 
well - the 'properties' dialog of the personal calendar gives "/home/karsten/.local/share/
apps/korganizer/std.ics",
but "/home/karsten/.local/share/apps" does not exist on my machine..)

Any ideas on this?

thanks -
Karsten