I was surprised to discover that “option straddling” doesn’t work this way with nargs="*". It seems to work fine with most other kinds of positional arguments I have tried, and I imagine that this was by design rather than accident. Many Gnu CLI programs also tend to support it as well (e.g. “cp file1 file2 --verbose dir/”).
I assumed nargs=argparse.REMAINDER was intended to override the “option straddling”. Otherwise, by just going off the documentation it sounds like nargs=argparse.REMAINDER is much the same as nargs="*".