While using this add on Malwarebytes popped up with 24 warning messages as it blocked numerous malware, adware, Trojans, and other malicious websites that were trying to be opened in Firefox. I was just scrolling from month to month, not selecting any links. Some of the websites were in my history, some were not.

I don't know why this happened but I'm not going to spend the time trying to figure it out. I uninstalled the add on to make it stop.