The highest I have ever seen my aps get up to with the flying dragon cubed is 2.51.
Even using the reduced multiplier that Quinn69 talks about in his generator build, a factor of 1.8 rather than the double listed in the description of flying dragon, wouldn't I expect my highest aps to be over 3?
Is there something bugged with my cubed flying dragon, or am I not understanding how it works?
I think I had a bug once with a cubed item not working... not sure which one, but for me it was simply leaving and rejoining the game to get it to work (you might also change the cube item and switch back). Note that it's a proc, so maybe you're just unlucky with not getting procs? Note that at 2 APS you need to hit quite for quite a few seconds before seeing an FD proc.