You have found one more of the major flaws with Affinity's applications, the boolean operations don't work with straight line segments, or open curves.
You could try adding all the curves which make up the segments and then try to divide.
Unfortunately Affinity Designer's Boolean Operations only work with closed shapes (unlike most other vector based software), i.e., they won't currently work using lines, hence why the Xor fails. Hopefully this is an area that will be vastly improved whenever v2.0 is released... 🙏
A few options depending on what you're trying to achieve...
Expand your lines...
pie_01.mov
If you want a hole in the middle of your circle...
