If we change the region on the Xiaomi smartphone, a second clock is displayed on the lock screen when the times differ, and this feature can be turned on/off and the region of the second clock can be changed.

Android 10 (MIUI 12.0)
Step 1:  Open the  Settings
Step 2:  Tap on  Additional settings
Step 3:  Tap on  Date & time
Step 4:  Enable or disable  Dual clock
  1. Open the Settings
  2. Tap on Additional settings
  3. Tap on Date & time
  4. Enable or disable Dual clock

Xiaomi Instructions