There is a bug in Ubuntu update which causes malfunctioning of the virtual keyboard switch on/off. We found Block Caribou extension which can fix the issue.
The steps are:
Step 1
Find Caribou extension.
Step 2
The extension will open. Just click on the top left button <.
Step 3
Select the extension, Install it and confirm the installation.
Step 4
Go to the Extension settings.
Step 5
Switch Block Caribou on.
Step 6
Restart PC.