Try to add this snippet anywhere in your code:

    r'('

Besides broken regexps, PythonImproved still doesn't highlight async/await, highlights raw docstrings as regexps, incorrectly handles implicit line continuations in function parameter annotations, etc.

Edit: here's an issue that documents some differences [1]

[1] https://github.com/MagicStack/MagicPython/issues/3