SUMMARY
With Yakuake running, pressing the shortcut makes it drop down, and pressing it again makes it go away. But if you click something else (or run a command) to make it lose focus when it's dropped down, it stays, though naturally falls behind what you gave focus to. Hitting the shortcut now doesn't bring the existing window to the front, but makes it silently disappear in the background, and you have to hit it again to make it appear again and drop down. It behaves as if the "Keep window open after it loses focus" setting was enabled, but it is not, and toggling it on and off again does nothing.

This is on Wayland. I could not reproduce it on my X.org user.

STEPS TO REPRODUCE
1. Start Yakuake
2. Ensure that "Keep window open after it loses focus" is disabled
3. Hit shortcut to make it drop down
4. Click outside the console window

OBSERVED RESULT
5. Console window stays but loses focus
6. Hitting the shortcut again only makes it go away in the background
7. Hitting the shortcut a second time makes it appear and drop down again

EXPECTED RESULT
5. Console window is hidden
6. Hitting the shortcut again makes it appear and drop down

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Manjaro x86_64, KDE packages from repositories
KDE Plasma Version: 5.23.3
KDE Frameworks Version: 5.88.0
Qt Version: 5.15.2
Graphical Platform: Wayland
Graphics: Intel

ADDITIONAL INFORMATION
This is a new user I created to try Wayland with, so settings are (mostly) defaults.

I looked at https://bugs.kde.org/show_bug.cgi?id=433171 but I'm not sure it's the same bug, as for me the window does go away if I hit the shortcut.