I tried some of the suggested solutions to the brightness bug but they didn't work for me.
I found a temporary solution to the brightness issue, but it works on the currently selected window (the brightness of that window will be affected and not the rest of the desktop).
You can go to Menu -> Preferences -> CompizConfig Settings Manager
In "CompizConfig Settings Manager" enable (check the box) "Brightness, Brightness and Saturation" then click on this item.
Choose the Brightness tab. There you'll find 2 keyboard icons and 2 mouse icons. What i did is next to the keyboard icon with the title increase, click on the "Disabled" button then check the box to enable this feature and then you'll be able to configure the button that will control increase of brightness. Click"Grab key combination" and then press the key you would like to assign this task or you can press a combination of buttons (ex. Ctrl+F6). Do the same to decrease the brightness.