Comment 6 for bug 1564137

This is indeed an addon problem. I'll tell the Ghostery developper and ask a fix.

For now, the solution is to allow the trackers inside the customer interactions category, or as in my case, the trackers in "Signallers" category.

That's still weird; I configured my Ghostery to allow trackers from first-party websites (like, allow youtube trackers at youtube.com).
This bug shouldn't happen according to my configurations...