Please refer to the following troubleshooting steps:
1. Place both earbuds back in the charging case, close the case, then reopen it and take the earbuds out again. This action can help reset the Bluetooth connection between the earbuds and your device, potentially resolving any synchronization issues;
2. Open the Xiaomi Earbuds APP and bind the earbuds to the APP. Check for any available firmware updates, as an outdated firmware version could cause audio sync issues. You can view the current firmware version at the bottom of the device details interface in the APP;
3. If the problem persists, try resetting the earbuds. To reset, press and hold the button on the charging case for 10 seconds until the indicator flashes. After resetting, reconnect the earbuds to your device and test if the sound is now in sync.