Why does the phone sometimes not vibrate under Vibrate in silent mode when receiving APP notifications?

To resolve this issue, please refer to the following steps:
1. Please ensure that Vibrate in silent mode is enabled on your phone. Path: [Settings] >> [Sound & vibration] >> [Vibrate in silent mode];
2. Check if vibration is enabled for the APP under notification settings. Path: Press and hold the APP icon on your screen >> tap the information icon >> [Notifications] >> enable [Vibration];
3. When the phone is in Silent mode with Vibrate in silent mode enabled, to prevent frequent disturbances, the system is designed to skip vibrations if multiple notifications from the same APP are received within 15 seconds. Specifically, the phone will vibrate only for the first notification during this time frame, and subsequent notifications will not trigger vibrations. This behavior is by design and not an issue.