it’s happened twice so far in the last two months, for internet explorer and winRAR, despite having these programs ignored, I got a pop up from avast telling me an update was available for them, and I had to set them to be ignored again
using avast pro 11.1.2241
Update to the latest version (2016.11.1.2245): https://forum.avast.com/index.php?topic=179855.0