It's probably worth looking into why that's happening if you are able; whether nyx/stem/python is somehow causing that, or if it's something wrong/weird with your machine.
Looks like the same bug (or a very similar one) has been found before: https://trac.torproject.org/projects/tor/ticket/9804
If something is manipulating envp, args, etc directly that might be it as the usual set of env syscalls shouldn't corrupt things.