This does appear to work fine.    I dunno if AMD is gonna release an official driver with this fix or not, but in the mean time it looks like a viable solution.

I tried on 2 rigs, both with rx580.       Speed went back up from ~28.4 to my initial 30.55MH per card.

1- Make sure you update to claymore 9.8
2- OC and voltage control DO work with BETA version of MSI AB. (link in above post, msi afterburner 4.4.0 BETA 15 )
3- Make sure you apply atikmdag-patcher before system restart

Will deploy to my other rigs soon