it's the KB5003124 Update which comes with 21H1. Uninstall that update and things returns to normal. It affects several stardock programs including windowblinds, groupy, and windowFX. Look for it in Feedback hub and upvote it please.

THe latest beta works for me now. I got hit with the new update today and i have the groupy and WB beta's installed. They didn't exist when I posted that.

you guys fiddle around with your pc's to much, and cause yourselves unnecessary problems... lmfao

isn't the latest Windows 10 build 20H2 (OS Build 19042.1052), after the updates? After installing Windwoblinds 10.8.9.0 beta I started having issues with the system tray/taskbar area, it would get all garbled up, I'd have to move my taskbar into the vertical position to fix it, then move it back to horizontal; this happened every time I'd apply my skin I was working on in SKS, got annoying, so I turned on/enabled  "News and interest" to show icon only, and it's been working fine (for now). 

Are you sure installing WB had any impact on this?

There is a serious bug in the latest OS update, but WB isn't one of the apps that exposes it.  Fences will, Groupy will, WindowFX will, some other apps including some MS ones will but as best I can tell not Start10 or WindowBlinds.

Do you have any of those installed?

When skin from WB is enabled you must choose "News and interest" or "hide icons"

Ok Neil, I've done an update (Foreced) of Win 10, apparently my system didn't update to 21H1, I was still on 20H2, so after the update to 21H1, it's been fine, and I wasn't trying to say it was WB, it just seemed coincidental, that's all, Cheers.