When I use the Cmd ⌘ Ctrl ⌃ Space , It does not open the Emoji viewer, but opens a 'Search My Mac' in the Finder.
You need to make sure that key combo hasn't been set up as a new command in System Prefs > Keyboard > Shortcuts > Spotlight
Default should be Cmd ⌘ Opt ⌥ Space
You could also check it wasn't added as a specific menu command in App Shortcuts...
...which would then show in the Finder's File menu too [together with a new 'Find By Name' item] compared to the original using Cmd ⌘ F