Language setting issue after updating to macOS Tahoe 26.3.

After updating to macOS Tahoe 26.3, my MacBook Air (M2 with a US English keyboard) is automatically changing keyboard language settings, ignoring my preferred configuration: Italian as the system language, Japan as the region, US English as the keyboard language. This issue first appeared when the MacBook stopped recognizing the correct login password because it had switched the keyboard language to Italian without notice. Although I can manually reselect US English, the setting reverts after each restart, switching between Italian and Japanese. Multiple configuration attempts failed to resolve the problem. The MacBook can no longer maintain my preferred configuration, which worked perfectly before the Tahoe 26.3 update, forcing me to adjust the keyboard language settings at every login. What should I do?