It was patched for almost all systems almost immediately like he said. I suspect the reason he still had the bug was due to the Asrock Rack X470D4U motherboard being an older generation board, and also a micro atx server board of all things. They might have only sold a couple hundred of them total in a niche like that so it's not too surprising it would be a low priority on the bios update list.

I also find it kind of funny that he calls Asrock Asus every single time he mentions them in the article. If he was trying to install an Asus bios on his Asrock mobo then he's got bigger problems than this bug.

Hmm, I guess that makes sense save for why wasn't the OS supplied microcode working or why was it out of date.

So if I was to build a Ryzen System today, would that bug not exist?

You would definitely be fine as long as you're using an updated motherboard with at least AGESA 1003ABB, which would be any x570 board and likely the vast majority of x470s by now.

Last time I checked, this was not fixed for my B450-TOMAHAWK-MAX

Hmm, I see 1.0.0.3abba was released for that board on 9-18-2019. That should include the fix, although I'm not an expert, maybe it isn't there for some reason?

Last time I checked it was only BETA - I will check again to see if anything has changed.

EDIT: looks like it's out of beta now - awesome! Thanks.