So, Im having a couple of weird bugs with this in 60.9.0esr (32-bit being mandatory for me for hangouts phone). I leave it on all the time, and it has started rendering sites even whiter than they would normally be. This is only corrected by the very awkward process of turning night mode on and back off for each site. It also appears to be making whole pages unreadable on the gizmodo family of sites (the text and background are white, same with links) - this stays an issue with it on or off, just have to load them in another browser for now. I use this as a portable version, so if you wish to test it on this, its easy to grab the portable.