@jwms there are more than a billion routers each ASUS, Linksys, Dlink, Ubiquiti, Cisco, Netgear, Arista, and many others doing 3rd party domain name checks every day; every DNS request is considered 3rd party because none of the router vendors actually own any DNS service. 

Per US DHS, CISA, and Interpol, Linksys, DLink, and Netgear are hijacked and used for DOS than any other brands. TP-Link isn't even in the top 20%. 
 

Sone of those vendors have major yearslong issues of never fixing any security flaws in their routers, such as Netgear, Linksys, and Dlink, all way worse than TP-Link. Every router brand has had major security issues this year, many having more security issues than TP-Link.  
 

Fact:  The primary reasons the investigations of TP-Link were started because TP-Link used to be Chinese-owned. 
 

Fact:  The vast majority of claims against TP-Link have been found to be false and to be entirely based on politics and/or racism.

  @Richardj186 Can the feature be removed and the product still function?

I only mention the recent events as one reason. Aside from that, it serves no purpose as I have other more elaborate network equipment that does need 'connectivity checks' to operate in the same manner which leads me to the conclusion that it is a superfluous command in the firmware.