Currently running version 17.1.1. Problem persisted in older versions with wattman. Did numerous DDU clean installs.
To put it simply whenever I try to select the manual voltage in Wattman it completely messes up the screen like somethings terribly gone wrong and the display drivers crash and does not recover without a restart. For now I am stuck with the automatic voltage feature but it is given me terrible underclocking/overclocking results +20/+40 on the core/mem is the max I could get from it. Before I was getting +70/+80 for less voltage!
CPU - Intel I5 6600k (4.8GHz, 1.38v)
GPU - Sapphire Nitro R9 390X
Memory - Kingston Hyper X DDR4 3000MHz (2x8GB)
Motherboard - MSI Z170A PRO CARBON
HHD - Western Digital Blue 1TB
SSD - Kingston Hyper X Fury 730 128GB (Drivers installed on), Crucial MX300 750GB
Monitor - LG-34UM65 (2560x1080)