UPDATE Solution(??) It looks like AGESA AMD BIOS version Patch B (1004 B) is working for folks with Asus Prime X470 Pro and MSI B450 Gaming AC.  That may be the solution.  Check your motherboard manufacturer's website to see if the latest BIOS includes this version, test it out, and report back.   ----------   UPDATE - As of August 2019, it looks like AMD Tech Support addressed this issue.  Unsure how long it will take to roll out to your mobo manufacturer: