Bug 476953

SUMMARY
When using multiple keyboard layouts the "Meta" key (aka Super or Win or Command) will only use the default layout rather than using the currently chosen layout, breaking keyboard shortcuts. 

On my setup I have "Dvorak" as my primary keyboard layout and "Qwerty" as an option for people who use my computer. However, when they press Super the keys revert to dvorak, so they have to press the dvorak location to use a key. For example, I have meta+w assigned to close the current window, and while Qwerty is selected they have to press meta+comma to close a window, instead of meta+w.

If I switch the order of the two keyboards the problem reverses, now when dvorak is selected I have to use qwerty keys while holding down meta. 

STEPS TO REPRODUCE
0. These steps assume you have "English (US)" with no Variant as your default keyboard layout
1. Open System Settings -> Workspace -> Shortcuts -> KWin -> Close Window
2. Set Custom Shortcuts to Meta+W, click Apply
3. Press Meta+W, observe that the window closes
4. Open System Settings -> Hardware -> Input Devices -> Keyboard -> Layouts
5. Click "Add" to add a new layout
6. Select "English (Dvorak)"
7. Click "Apply"
8. Switch to the Dvorak layout (I use the icon on the right side of the start bar)
9. Hold down Meta and press the key to the right of "M" (this is W on Dvorak)
10. Observe that the window does not close, even though you just pressed Meta+W
11. Verify that the keyboard layout is still set to Dvorak, but press Meta+Qwerty W
12. Observe that the window closes, even though you just typed Meta+Comma
13. Swap the order of the keyboard layouts and try steps 8-12 again, observe that now when holding down Meta all the keys correspond to Dvorak.

OBSERVED RESULT
While holding down Meta the pressed keys correspond to the First keyboard layout.

EXPECTED RESULT
While holding down Meta the pressed keys correspond to the Selected keyboard layout.

SOFTWARE/OS VERSIONS
Windows: 
macOS: 
Linux/KDE Plasma: 5.27
(available in About System)
KDE Plasma Version: 5.27.8
KDE Frameworks Version: 5.110.0
Qt Version: 5.15.11

ADDITIONAL INFORMATION
Only tested in X11, not tested in Wayland