constexpr variable 'HeaderOffset' must be initialized by a constant expression

I am facing an error when using shiboken to compile some code of mine:
QtCore/qplugin.h(146,33): error G3F63BFAE: constexpr variable 'HeaderOffset' must be initialized by a constant expression

see this stackoverflow post about it https://stackoverflow.com/questions/78770245/shiboken6-constexpr-variable-must-be-initialized-by-a-constant-expression

I have tried several combinations if compiler arguments but it seems to be an issue with CLANG not recognizing the correct implementation of offsetof.
I was able to build the code on one machine, but on a build server it does not work. I am not sure if this is actually a bug, but it seems like a bad combination of settings, which could be one.

Sorry if this is not the right place to post this.