1 pointMost likely it happens while attempting to import the ESET root certificate to the trusted root CA certificate store. We'll try to make a tiny change in the code to do it completely silently. You could temporarily disable this option for a test and see if the behavior is gone (don't forget to re-enable it):
1 pointHello, this could be caused by importing our certificate for scanning the SSL communication. Even if it is not your default browser, we do that for all supported browsers installed on the machine. We do call the firefox.exe process during the certificate import, that's why it could be seen for a split second.