This is a bug listed here:
https://bugs.launchpad.net/ubuntu/+source/ibus/+bug/1885914
The solution that I found is to remove the ibus package:
$ sudo apt-get remove ibus
$ sudo apt-get purge ibus
Go to updates and set the repository for focal fossa version for Ubuntu and remove the remanescent eoan
Go to updates and set the repository for focal fossa version for Ubuntu and remove the remanescent eoan and reinstall ibus:
sudo apt-get install ibus
Go to language suport and set the iBus method, for user and root
In the terminal for user and root:
ibus-setup
and change the shortcuts in the emoji tab
In the terminal for user and root:
im-config
and set ibus
For user in the terminal:
gedit .bashrc
Include the following lines at the end:
export GTK_IM_MODULE=ibus
export XMODIFIERS=@im=ibus
export QT_IM_MODULE=ibus