I'm using Bitdefender and all my results in google, after installing this plugin, have that blue line below :
block trafficlight.bitdefender.com

If I block ONE Pinterest result for example, or any result, then all of Google's results pages appear : empty, whatever I search. (then I have to unblock that or deactivate this plugin)

Most good security solutions check your webpages results before you click on them. And "Personal Blocklist" doesn't see the real URL, but the one modified by Bitdefender (just a guess) before it's displayed in Firefox.

I tried to turn ON/OFF all Bitdefender's Web Protections to find the one responsible but I couldn't. Sometimes they're all ON (Scan Web Traffic for Malware, Scan SLL, Protection against Phishing, etc) and Personal Blocklist displays the proper address in Google's Results and sometimes some are OFF and the Google results are all : "block trafficlight.bitdefender.com"

There seem to be a fault in Personal Blocklist that catches Google's URLs as they are, even when a part of the URL is modified by the chosen Security Solution (At least Bitdefender).

Please have a look into that when you have a minute. Thanks in advance ;) I'm looking forward to put 5 stars, because without that... it'd be worth it ! :(
Sorry I couldn't find the precise Bitdefender protection causing that.