Eero uses Google and OpenDNS on its own?
Eero seems to be using both Open DNS and Google DNS, despite the fact that it's not configured to do so: it should be using ISPs DNS servers.
I have Local DNS cashing and HomeKit enabled, so Eero is setting DNS for each machine on my network to itself (192.168.4.1). However, when running https://www.dnsleaktest.com/, I can see that my queries are being sent to public DNS servers, and not my ISP's one, despite the fact that It should (I can see correct DNS address on the WAN interface). No where have I specified that I'd like Eero to use either Google or OpenDNS.
Any ideas why that is and how to stop it?
That's unfortunately not it. If I point DNS on my machine directly on the DNS Eero should be using (126.96.36.199), the only result from DNS leak is that DNS (Three Ireland). THis is also the case if I put Eero into bridge mode and let my ISP's router do the DNS resolution.
It appears that Eero for some reasons on it's own choses to use 3rd party DNS despite setting that's in here.