DNS HIJACKING with a Separate firewall directly connected causes issues that can not be resolved.

I have a Pace Plc 5268AC with static IP's as Supplemental Network. IP6 is disabled. My Security Gateway that has a separate private network behind it, is connected directly to the Pace router and is assigned in the Pace router with a static IP with firewall disabled and is set as part of the DMZ. 

Some network glitch occurred and now select domains are being hijacked by the Pace router for traffic only coming from the Security Gateway. I have attempted to change the IP of the Security Gateway and rebooted the Pace router multiple times. 

I define hijack by going to the domain foo.bar in a computer behind the Security Gateway, the browser is redirected to http://attlocal.net/xslt?PAGE=HURL00, but the attlocal.net is not directed to the Pace router. The domain attlocal.net is only available through the Pace DNS on the Private network of the Pace router. 

When a computer is connected to the Pace router directly and it gets a private IP from the DHCP and this happens, the page is sent to the Pace Routers error page that clears the issue in the router and allows the browser to reload with the domain that was originally hijacked. 

I can see the pages being hijacked in the Event Logs with the filter "hurl". This is affecting more than one computer behind the Security Gateway including Amazon FireTV's which can not clear whatever tag that causes the DNS hjack if they connect to the router. 

I understand the DNS hijack is part of a security feature that is to stop malevolent apps/computers/devices from causing issues, but unless there is a way to clear this via the router or another feature, can not happen when there is privately managed network equipment behind the Pace Router. 

What needs to happen to have this DNS hijacking stopped? 

Do I need to sign up for business services? 

Do I need to remove the Pace router completely with something else? 

Any suggestions are appreciated as the rest of the forum posts don't have any resolutions that match this issue, but a lot of similar posts are probably caused by this exact issue of private network equipment behind the Pace router and that router trying to "protect" the user.