@ThomasMockridge 

When does this error occurs?

Were you executing a specific action?

  @yves_b 

It happens on every DHCP query so the DHCP allocation takes a few minutes to resolve to a new address... Which in my case is the same address. As I use DHCP reservations,

You can see the error if you run "ipconfig /renew" before you are reconnected to Wifi. Then the Windows arp probe gives address in use error. It is probably due to an incorrect reply to the arp request to the Deco - address is not in use yet (But was, so is still cached) This command avoids the incorrect arp response or waiting a few minites for the Deco to expire the cache entry in the arp table.

This issue is not limited to TPLink many routers have this issue (Even older Cisco devices!)