DNS Leak issue with NordVPN

Last week, I used diffrerent DNS leak test tools to check NordVPN such as
http://dnsleak.com/


These all tools showed two ISPs h have right to use my internet information. Why it do this?

Usually the ISP DNS is in the same subnet as the WAN interface and uses it for the shortest route:
https://openwrt.org/docs/guide-user/base-system/dhcp_configuration#dns_provider