Same problem

Another one to add to the list, the WA1201 also has the bug.  In fact from having read through this entire thread, after finding it while searching for a solution to the problem with the WA1201, it looks like it's endemic to all TP-Link wireless products.

This is a pretty ridiculous situation, I've never before encountered a wireless AP that's unable to tell you what's connected to it.

Talked to a friend of mine earlier who does this sort of thing for a living, as soon as I described the problem he said "what they're doing is taking the client list from the ARP table instead of the WiFi-connection table".  This matches the comments from @Carl about it being ARP-related, but that's not an excuse for why it's happening, it's a description of a serious flaw in the TP-Link firmware which seems to exist throughout their product line. 

In other words the response shouldn't be "well it happens because of this", it should be "we've now identified a design flaw in how our software works and are working on a fix".  The client list should not be built from the ARP table but from the WiFi-connection table.  This then also allows the device to show attempted-but-failed connect attempts, which is essential when you're trying to debug failed-auth problems and similar.

Someone or even tp link found a solution yet?

Same issue here

Brand new Archer C6.

Some 20 clients successfully connected to the Archer - all fully working - only 6 showing up in the client list.

I spent €85 and can't even see the full list of devices in my network. It has been almost TWO YEARS and still no fix for a simple thing like this.

A great reason to stay away from any device from tp-link for the rest of my life.

Brand New out of the box AC1750 same issue .. no Clients -- everything is connecting and working well but no list ... this sucks

  @IronAddictAZ Return it if you still can.  Stay away from this company for wifi routers, they aren't supporting them as well as other vendors.

  @alien-link 

Crazy! 3 years and still the same bug. Good that it happened to me now, that I need to buy a lot of devices... At least this helped me to decide which brand I shouldn't buy