Please install Crimson 16.8.3.
I had the Flicker and Negative Scaling Issue on my system i74770K, GPU1 = Sapphire HD7970 OC 6GB, GPU2 = Sapphire R9 280x OC 3GB.
Note my cards are not on the Crossfire Compatibility chart.
For me negative scaling is fixed since Crimson 16.8.1.
I get FPS improvement of 1.42 in the Division on Ultra and can run at 56-60FPS at 1080p.
I have to turn off Frame Rate Target Control and Frame Pacing otherwise any Crossfire title I run will Crash or Freeze.
Hope this helps.
You want to ask AMD directly then, as the response you get on this forum is from another user....and is their opinion only. You can do that several ways including a telephone call, however the most practical way is to e-mail them > Email Form