Issue with Vietnamese keyboard input source on MacOS 10.15.6

Hi everyone,

I just have an issue with all Vietnamese keyboard input sources. When I switch to any input sources (Telex, Simple Telex, VNI, eg.) and typing keyboard, no character is displayed on screen. But if I switch back to US input source, everything works fine.

I tried to create and change to new account or using Guest account but the issue is disappeared.

Do you have any ideas or solutions to resolve this problem without reinstall macos?

Thanks.