We have been unable to reproduce this issue so far, the clocks reset to the default values as expected.
Below are the steps we took and the specs of the systems we tested:
Ryzen 7 1700X
HD 7870/R7 370
Win 10 RS4 +
We're going to need alternative instructions on how to reproduce this issue.
Start several Media Player Classic windows at the same time, also you will reproduce uvd bug. How so left that we people the bought AMD cards have to beg you to correct your errors?
That's not how you do it.
Open Chrome. Open Facebook. Scroll down and trigger the HW Acceleration clocks, in my case 501/1500. Once they're there and not going down, you open a video in MPC. See how the clocks go to 850/1500. Close everything. The clocks are now stuck...
If this sounds like a far fetched scenario, it happens to me every damn day. I'll open Chrome, send messages on Facebook, check my feed, trigger the HW Acceleration clocks, forget about it and then open a video somewhere, say a movie. Get stuck on UVD clocks and only remember it later. This is not a nice thing to happen and it happens to me every day. The drivers don't function right. It was all good until 16.7.2....
You are most probably failing to do the detail what I've underlined twice in the instructions, because your reproduction steps don't mention it properly. When you scroll enough in Facebook, clocks must jump to 450/1200 on a 7870 or 501/1500 (as per maverique's 280x example) and remain there without going back to idle 150/300 even if you change a tab and let it rest for a while. This is very important. Only then you can launch MPC-HC to play a DXVA2 accelerated file to trigger the bug.
Btw, given that most clips on YT are VP9 accelerated under Chrome instead of DXVA2, they shouldn't affect the UVD.
We were able to reproduce the issue after opening Windows Game Bar. Once it is fixed it will be called out in the release notes of a future driver release.