Pit,

Thanks for reporting this. I looked into it and tracked down the issue to the following.
I have submitted an MR which will hopefully be merged soon.

I believe you compile from code, can you make the following change and test?
(I'd have you just use the latest code but I don't necessarily recommend you using that right now.)

In the file kstars/kstars/skycomponents/artificialhorizoncomponent.cpp
find the function called appendGreatCirclePoints (starts on line 268)
and comment out these 4 lines which are not far from the top of the function (lines 274-277)
invent.kde.org/education/kstars/-/blob/m...oncomponent.cpp#L274

    // std::shared_ptr<SkyPoint> sp0(new SkyPoint());
    // sp0->setAz(az1);
    // sp0->setAlt(alt1);
    // region->append(sp0);