Hi,
I am using the RX 460 and in 10.3.2, I can no longer wake from sleep, nor does the cMP actually go to sleep. The lights flash like it is at sleep, but, the machine is still on. I also cannot wake it up from sleep and have to shut it off by pressing and holding down the power button and restarting it again.
I don't recall this in 10.3.1, or 10.2.6 and earlier with my RX 460.