Which distribution and version?:
Arch Linux

Which desktop environment and version?:
KDE Plasma 5.27.10

Which session type?:
Wayland

Which application and version?:
All applications

IBus version?:
IBus 1.5.29-rc2

Issue description:
When changing layout with OSD visible (Holding down <Super> key and selecting layout with space) first key pressed after the change is from the previous layout. Sometimes OSD does not disappear until any key is pressed.

Steps to reproduce:

1. With default ibus keybinds, hold <super> key
2. Press space to select different layout (In my case, pair that causes the issue is Russian <-> US English)
3. Release space and <super> after changing layout
4. OSD may still be visible until any key is pressed. The first key pressed after change will be from the layout user changed from.

Note:
If OSD did not show up when changing layouts (user pressed the keybind quickly), issue is not present. OSD itself behaves in strange ways, disappearing while <super> key is help or changing layout order in the osd window itself.

Can you reproduce your problem when you restart ibus-daemon? (yes / no):
(Run ibus exit and ibus-daemon --xim &)
Layout switching does not work after the command, however tray icon is present.

Do you see any errors when you run ibus-daemon with the verbose option?:
(Run ibus-daemon --xim --verbose & and look at the output when you encounter your problem.)
Layout switching does not work after the command, does not print anything in stdout.

Can you reproduce your problem with a new user account instead of the current your account? (yes / no):
yes, issue is present with new user account, default ibus settings, Russian and US English layouts.