KDE vertical panel with 'windows can cover' option does not work

I've done a fresh install of Ubuntu 22.04 LTS and added KDE. I've setup the main panel (with taskbar, etc.) to be options: windows can cover. Everything works as expected as long as the panel is horizontal. If I move it vertically, windows suddenly 'go under' it. The problem occurs even for a new, empty panel as long as it's vertical. Here's how it looks like. Added two panels: one horizontal (gray) at the top of the screen and one (also gray) on the right border. Changed 'window can cover' option on both and placed a terminal window over them. Only the horizontal one respects this setting: