Google KB4549951 and you'll want to uninstall it immediately.
I've seen no problems at all on my Win10 machine after KB4549951 was installed.
Maybe the 2nd update of KB4549951 (as I've shown in the first post) was to correct the issues seen when it first came out (?). I highly doubt Microsoft is going to sit back and do nothing when so many people see issues from one of their updates.
Update - I also noticed update KB4550945 (link below) was done on 4/23/20 on my Win10 machine. So this could be the correction to issues seen by some users in KB4549951.https://support.microsoft.com/en-us/help/4550945/windows-10-update-kb4550945
I agree that Microsoft needs get their act together on updates, and ring out updates more for problems before releasing them. I froze my updates for 7 days, and will continue to freeze them until I can verify there are no reported issues with new updates.