Hi, Cooker
The problem is usually caused by the packet loss and packet disorder in the customer network.
First, you need to optimize your network environment.
Besides, you can change the configuration in the CU and the camera to reduce this situation, change the transport protocol to TCP to re-send loss packets, Reduce the bandwidth usage, and change the protocol to H.265 to decrease the network usage and avoid to overwhelm it.
Other cases:
1. Check whether the device configuration meets the requirements.
2. Check the device load.