Can you also see if this bug happens with the latest upstream stable 4.4 kernel? It can be downloaded from:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.4.19/
If it does still happen with 4.4.19, we can perform a reverse bisect to find the fix that is in 4.8-rc3.
Can you also see if this bug happens with the latest upstream stable 4.4 kernel? It can be downloaded from:
http:// kernel. ubuntu. com/~kernel- ppa/mainline/ v4.4.19/
If it does still happen with 4.4.19, we can perform a reverse bisect to find the fix that is in 4.8-rc3.