www.dns0.eu is flooding log

dns0.eu is the new DNS resolver for the EU, driven by the founders of NextDNS.
I am an experienced user of NextDNS and started to set up my router to dns0.eu (IPv4/IPv6/DOT) as the main DNS resolver for all queries not using NextDNS by DOH(guests, set top boxes, IOT...).
Since my webbrowser is set up using NextDNS via DOH I found a lot of hits as x.test.dns0.eu (where x is 15 digits og numbersand letters) in my NextDNS log. If the page www.dns0.eu is just open, I got about 210.000 hits within 30 minutes! See attachment (screendump from mobile).
Not just as my free limit of 300.000 free queries / month is nearly reached, it might be a configuration error and cannot be intentional. I have noticed the green bar on the bottom of the browser window which showes "You are using dns0.eu" which dissapears immediately if I switch over to NextDNS for the webbrowser, e.g. by using the NextDNS app.

Be aware of using dns0.eu with your NextDNS account setting in the browser or via the app. Or is NextDNS willing to reset my "free quota" of 300.000 queries?