5.27 is the first KDE release in a while that has actually broken things for me. Fedora recently updated to it and the breeze theme broke, causing me constant crashes and glitchy window decorations.
Yeah. In my case, the Discover app didn't fully update all of the packages like it was supposed to. Easy enough of a fix, though I doubt an average PC user would have been able to figure that out.
Discover really has never worked all that well for me when it comes to updating packages. I have used the terminal to install updates for a long time now, with both Ubuntu and openSUSE.