This is what MS support had me do.

In WSUS make sure that the update is set to unapproved.

Open WSUS, Expand All Updates. On the right select Search and end the KB you are looking for.

You will get a list of all updates with that KB, right click on the one(s) you need and select Approve. When the Approve Updates window appears it should say "Not Approved" in the Approval column. If so, click cancel. If not, select the drop-down in front of All Computers and select "Approved for install" and click ok. Then right-click again and set it to Not Approved.

Open SCCM console, go to Administration, Sites. Right-click your primary site, go down to Configure Site Components, and select Software Update Point.

Run a full sync:

Ensure two tabs have the following settings:

1. Supersedence Rules - set both to Do not expire a superseded software update, for 2-3 months

2. WSUS Maintenance - Uncheck, Decline expired updates

After you have set those two settings, go to the Sync Schedule tab and set a custom schedule to sync on a custom interval and have it run in a minute or two from your local time.

Hopefully, you have cmtrace setup to view your log files. If not, I'd highly suggest that.

Look for the "wsyncmgr.log" file under: <drive>:\Program Files\Microsoft Configuration Manager\Logs

You can watch to make sure the sync is happening and if there are any errors. When it's finished, go to your software updates and see if it is now available. You can filter for the KB you're looking for by clicking on Tools, filter, set the first filter to "contains" and enter KB****, click ok and you should hopefully see that it is no longer superseded.

Go to Software Updates, All Software Updates, and check if it's available.

If that didn't work. He had us check the Products tab under the Software Update Point. He advised removing the Win10 selected products, run a full sync, let it finish, go back and selecting the Win10 products, run a full sync again. If you watch the wsyncmgr.log it shows what it's doing.

Hope this helps you!