Barefoot_Monkey: As far as I can see it's all to do with the angular injector working oddly in Firefox 53, and not because of anything you did, and having both of our scripts just happens to cause a problem. I have some ideas that I'm looking into that might solve it.
FWIW, I have the same problem, except that BE also doesn't work on the front page with AF enabled, and I"m on Firefox 52.0.2 (32bit, EME-free), and not 53.
As a workaround, I've added the code to restore the BE link in the account tab to v.2.14, which works with AF enabled, and added the tweak to get rid of the dimming to my GOG userstyle file.