on iPhone ignore app DNS


I was troubleshooting why my iPhone 7 Plus with iOS 13.1.3 is not validating my broken dnssec domain.
What I found is:
Chrome, App Store, Safari, etc. all of this app’s ignore app and all dns traffic go to my default resolvers (from dhcp). All I checked on my router with tcpdump and it confirms. Same behavior is on cellular network.

ISC Dig see resolvers in iPhone and use it correctly.

I had same iPhone 7 Plus (factory settings) with same iOS 13.1.3 and it was same.

It doesnt matter if i use DoT or DoH.
Dnslog is empty, except dns traffic from app or request from ISC Dig App.

What do you see at ?

But no DNSSEC validation?

Any update?