Azerty keyboard switch to qwerty when writing in Japanese and when logging in.

Hi,

I have bought a new iMac in Japan and it is working with macOS Big Sur. It was delivered with a Qwerty keyboard but I am using the AZERTY keyboard from my previous Mac because I am French speaking.

I have changed the languages in the settings (keyboard) and it works in AZERTY properly when I write in French. However, when I type in in Japanese, it automatically switches to QWERTY which is very annoying.

Moreover, when I turn the computer on, I need to enter the password in qwerty mode. From second time on, it is requested in azerty. I don't understand why those switches between AZERTY and QWERTY happen. Any idea?

Thank you very much!