This is almost certainly being caused by Avast.
Here’s another person with maybe the same issue: https://forum.avast.com/index.php?topic=320246.msg1690321
If you are paying for the product I suggest getting in touch with their Support. Most likely what is happening is it’s attempting to ‘protect’ you by blocking processes/apps on your computer that it doesn’t know about, and it doesn’t whitelist the Brave browser, so it blocks it.