@Virgo I am pretty sure it is not some devices I connected through a wireless network or LAN. I also have Mac address filtering in all my wireless networks. These Mac addresses show up only on the switch's port that EAP653 is plugged in. There is nothing plugged into that port other than EAP653. It always shows up as a device on the management/main network vlan even though it doesn't have any IP.  I also have separate vlans for all my wireless networks, so if it is connected through wifi it should get those vlans instead.

I also have a EAP610 that do not have any of these issues with the port it is plugged in. That is why I found this weird.

  @gautamkrishnar are you using a POE adapter? POE Adapters do have MAC addresses and wondering it is somehow showing up.

  @RickJamesBish Nope, I am using TL-SG2210P v5.0 switch, which already has POE built-in. Following is my setup:

  @KimcheeGUN 

> The 1st thing is... those MAC addresses do not come with any vendor ID. 

Yes that is why it looked strange to me.

> What type of devices are connected to that AP? 
Laptops, mobiles, and some Tuya based IOT Devices are connected to that AP. All IoT devices are on separate VLANs and they are connected using separate SSIDs. If some devices are connected through the wifi network, it will show up in the client list under the wifi ssid right. The strange thing is, none of these devices shows up as connected via wifi network. It just shows up as it is plugged into the same port as the AP. But it's not technically possible since AP does not have an ethernet port.

> Try disabling Meshing on the controller?  

It is already disabled. I enabled it once and turned it off back.

  @gautamkrishnar 

"The strange thing is, none of these devices shows up as connected via wifi network. It just shows up as it is plugged into the same port as the AP. But it's not technically possible since AP does not have an ethernet port."

The devices mentioned, are they connected directly to an AP wirelessly or do they go through any other type of device?

In the example below the camera in each scenario will show up being wired to LAN Port 1.

  @RickJamesBish 

> but do you have any devices that may be connected in that manner? 

Nope, I actually have 2 EAPs: EAP653 and EAP610. Both of them do not have a spare Ethernet port. I connected both of them to the switch using the only ethernet port they have.

EAP653:

EAP610:

  @gautamkrishnar 

" I connected both of them to the switch using the only ethernet port they have."

And each device is connected wirelessly to the mentioned APs and not through some other device?

If that is the case then I am out of ideas unless those devices are internally creating a scenario that is similar to what I explained. 

Have you physically looked at devices to see if any of them actually have a MAC addresses that are the same, or very close to the MAC address anomalies you are seeing?

  @gautamkrishnar 

Just for the record in reference to MAC Addresses mentioned

Beginning with / potentially used by...

90-65 Intel and EM Microelectronic

5C-E4 Intel

C0-A0  Arris Group, D-Link International, Fairfield Industries, Eden innovations and Multi Touch OY

76-F9 unknown

Not getting a return on a MAC Address could mean it is spoofed, set manually, etc

You could try process of elimination. In the router or modem interface, kick or block that device and then see what stops working.