The problem in Issue18075 depends on the amount of C stack used on average during recursion because unlike Windows the Unix ports don't test if the end of the stack is reached but just check for a maximum recursion count.  It could well be that the problem in that issue don't happen at the moment due to small changes in either CPython or the compiler.  It is also easier to trigger the problem with a debug build.

I have no idea why the linker flag causes problems, I'd have to debug this myself.