I’ve had this happen, as well, and believe it’s a Windows thing. To mitigate the risk of DNS hijacking, I’ve turned to using static IP addresses for the DNS settings in my Windows 7 network adapters. I’ve been using Comodo Secure DNS addresses:
IPV4:::
Primary: 8.26.56.26
Secondary: 8.20.247.20
IPV6:::
0:0:0:0:0:ffff:81a:381a
0:0:0:0:0:ffff:814:f714
After making this change, the addresses are always in the adapter(s). The only time I get a DNS change notification is when using a VPN, but the adapters are still set to the Comodo addresses no matter what.