It seems like Regional Formats or language problem to me.
I installed new Ubuntu 24.04 in English (US) and the windows worked fine.
When I changed Regional Formats to Korean and reboot the system, the window problem started and remains.
I think the password/login process in Ubuntu has a problem with cjk language.
In Ubuntu 22.04, I installed 4 languages (English, Russian, Japanese, Korean), and whenever the login prompt appears, there were only English and Russian available.
In addition, I had to change the input language because the default language was set to Russian in the prompt no matter what the language order.
It seems like Regional Formats or language problem to me.
I installed new Ubuntu 24.04 in English (US) and the windows worked fine.
When I changed Regional Formats to Korean and reboot the system, the window problem started and remains.
I think the password/login process in Ubuntu has a problem with cjk language.
In Ubuntu 22.04, I installed 4 languages (English, Russian, Japanese, Korean), and whenever the login prompt appears, there were only English and Russian available.
In addition, I had to change the input language because the default language was set to Russian in the prompt no matter what the language order.