Firewall clash in Windows 10

Avast Premium installed on Windows 10 PC takes >5 minutes to shut down the PC.
When Avast Firewall Service is stopped, it shuts down in 10 seconds.
It appears both Avast and Windows Frewalls are both active and somehow clashing.
Is there a solution to this?

https://forum.avast.com/index.php?topic=234120.0