RBR850 issued 705k DNS queries in 7 days from Netgear specific domains

I have two Pi-Hole servers setup as redundant DNS servers connected via static IP addresses on the local network. Both P-H servers are pointed to Cloudflare DNS servers (1.1.1.1 & 1.0.0.1). The P-H setup worked flawlessly for 5+ years with very little intervention. Probably rebooted the two P-H servers a total of eight times over the years. Recently updated both P-H servers to Core v6.2.1. Still pointing P-H servers to same Cloudflare DNS servers. After P-H update to V6.2.1 I cannot resolve DNS from any device on the network. I see there is a 'bug fix' P-H release to v6.2.2 Ill install that P-H update soon and determine if that solves the DNS resolution issues. In the meantime, for a 'quick fix' while I sort out the P-H issues, I subscribed to NextDNS and pointed the RBR850 to the two NextDNS servers as noted in my NextDNS profile (49.90.28.227 & 49.90.30.227). Almost immediately the DNS queries began to skyrocket. I've got 101 individual devices attached to the RBR850/RBS850 network - 90 of those devices are WiFi devices and many are IoT devices. I could not locate the 'switch' to disable Parental Controls in the 850 web GUI. Just now I DID locate the switch to disable Parental Controls in the iOS Orbi app. Immediately disabled Parental Controls from the app. Will see if that action has any effect on the outrageous number of DNS queries.