Stopping Sanic always gives me an error

I have a very simple test Sanic app as follows, taken from the example page. When I Ctrl C to stop it, I get the following error:

*File "sanic-server.py", line 13, in <module>*
*    app.run(host="0.0.0.0", port=8000, debug=True)*
*  File "/home/mike/.local/lib/python3.8/site-packages/sanic/mixins/startup.py", line 209, in run*
*    serve(primary=self)  # type: ignore*
*  File "/home/mike/.local/lib/python3.8/site-packages/sanic/mixins/startup.py", line 880, in serve*
*    sock.shutdown(SHUT_RDWR)*
*OSError: [Errno 107] Transport endpoint is not connected*

This example is running under WSL, but also have the same app running on the Pi for testing and get a similar (but not the same error). Server is started as " python3 sanic-server.py".

app = Sanic(__name__)

@app.route("/")
async def test(req):
    return res.text("I\'m a teapot")

if __name__ == '__main__':
    app.run(host="0.0.0.0", port=8000, debug=True)