That shows up on a number of articles.
I assume the tablet uses a simple open dns to 8.8.8.8
I should say that I wanted adguard to remain on as that blocks one setting.
Seems simplistic.
iptables -I FORWARD --destination 8.8.8.8 -j REJECT
iptables -I FORWARD --destination 8.8.4.4 -j REJECT
Blocking Google DNS on MT300N V2 - Technical Support for Routers - GL.iNet