Egress Traffic

Hello, we have ingress traffic from a device connected to port 1 that is generating about 500 Mbps. We have another device connected to port 5, which is the egressing traffic. When we analyze the traffic to device connected to port 5 we see that all traffic comes for some time then there is a pause when zero traffic comes. Then it starts again then there is a pause.

When we do port mirror with mirrored port 1 to destination port 4. When we connect a device to port 4 we can see that all the traffic coming from port 1 without any pulse of traffic. So, this tells us that device connected to port 1 is working fine but switch for some reason pause the traffic when not mirrored.

So, what could be the issue? Since mirrored port works and destination port does not work I assume something wrong with the look up table or switch core.