I use an extension to always send the base domain of the target as the "Referer" and have not encountered any problems (or at least not any that I cared enough to investigate the cause for). It's absurd that Firefox still has this privacy leak by default considering how much they present themselves as privacy friendly.
Firefox some time recently cracked down on unnecessary referrers but they are still fairly conservative about it because it breaks some sites and if you are too aggressive about it then you end up with users assuming that's firefox not working properly.
