I have a setup where ISP provided router first router. I have always used a secondary router which manages all the internal devices and usually runs on a different IP address range. This way it becomes easier for me to change out ISP without mucking with my internal device setup and yes, I am aware of double Nats and I am fine with it. Secondary router is connected using network cable to primary router. 

I have used this setup for years with verity of different routers and they seem to work fine last one being Netgear RAX70.

Till I started using the AX11000. It seems that AX11000 is assigning ISP's routers client address to the connected devices instead of 10.10.X.X IP address that I have setup on the TP link router. I can see these devices show up in the ISP client view, which seems that AX11000 is simply acting as pass through to other router and using that routers DHCP server to dole out IP addresses (192.168.XX.XXX). Is there a way to setup AX11000 so it keeps the two-network isolated and just router internet traffic to ISP?

So, setup is ISP router --> AX11000 -> clients. Need is to keep the clients isolated to AX11000 and yet give access to internet connection to all the clients

thanks for any pointers

Andy