@Anton: If I understand it correctly, in that Ask Ubuntu answer you basically confirm the presence of this bug as worded in the bug summary. (I assume you are using wayland.)
And yes, Win/Super + Space is another thing. It's the default shortcut on GNOME to switch input source, and uses another mechanism compared to the shortcuts you can set in Tweaks.
@Anton: If I understand it correctly, in that Ask Ubuntu answer you basically confirm the presence of this bug as worded in the bug summary. (I assume you are using wayland.)
And yes, Win/Super + Space is another thing. It's the default shortcut on GNOME to switch input source, and uses another mechanism compared to the shortcuts you can set in Tweaks.