How to stop 16.04.2 with HWE kernel from updating to 4.4 kernels
I encountered this this morning, fortunately I stopped it before it installed the new kernel. The HWE instructions should have covered this IMHO.
To prevent future problems of this nature, just delete the linux-generic entries. Until you do this, you will have two sets of packages that can be updated with different kernels.
sudo apt remove linux-generic linux-headers-generic linux-image-generic
Future kernel updates will come through the linux-generic-hwe-16.04
package.