Okay, I've found how to reproduce it:
1. systemsettings -> Input Devices -> Layouts -> Configure layouts
2. Add Ukrainian and English layouts.
3. Place Ukrainian layout above English.
4. Now launch Inkscape. Keyboard shortcuts (Ctrl+Z, Ctrl+S) don't work.
5. Now Ukrainian layout below English and restart Inkscape - everything is fine.
Okay, I've found how to reproduce it:
1. systemsettings -> Input Devices -> Layouts -> Configure layouts
2. Add Ukrainian and English layouts.
3. Place Ukrainian layout above English.
4. Now launch Inkscape. Keyboard shortcuts (Ctrl+Z, Ctrl+S) don't work.
5. Now Ukrainian layout below English and restart Inkscape - everything is fine.