I agree that I have this error in Chrome and Brave.. and for a long time. Seems random, definitely not a specific website. It's as simple as hitting a download button, getting the 'save as' dialog, then the buttons are unresponsive so the dialog is stuck (even happened on Wincusto, but not every time).
But try using alt-tab to switch to a different application, then alt-tab back to Chrome/Brave (ie alt-tab twice), and the 'save as' dialog buttons return to being responsive. Saves you having to restart explorer. (Can't speak for Edge. Dont' us it.)