Please Assist me in Troubleshooting

Hi guys, I’ve been a long time using of the Mikrotik devices and I really enjoy their flexibility, and price point. There is so much to them that I do not understand yet, but I’m hoping you guys might be able to shed some light on my situation.

The situation is this, I’m on a cable modem, I have 1 gateway (ether1) and 1 LAN port (ether2) and for some reason I’m seeing ~3.0Mbps in the Tx field of my LAN port, but no corresponding Rx in my Gateway. Can anyone tell me how this would be possible? I dont see why any packets would hit my LAN port if not destine for the WAN.

Additionally, I have run the packet sniffer and selected TX direction, and ether2, but I get no data. I then select RX, and same interface, and I get TX data. I am far from a network guy, but I’m trying to learn more, so if anyone can help me on either of these questions, it would be much appreciated.