Does that mean that your router is using Pi-hole and
220.127.116.11 as its upstream DNS servers? What is your motivation for using Pi-hole as your router's upstream?
If it is using
18.104.22.168, that would allow your router to by-pass Pi-hole.
But that maybe of little relevance, as your DHCP clients would use Pi-hole for DNS anyway:
Your debug log shows your router is distributing two private IP addresses as local DNS servers (presumably your two Pi-holes):
*** [ DIAGNOSING ]: Discovering active DHCP servers (takes 10 seconds)
Scanning all your interfaces for DHCP servers
* Received 300 bytes from eth0:192.168.4.1
Offered IP address: 192.168.4.178
Message type: DHCPOFFER (2)
--- end of options ---
By enabling Conditional Forwarding, your Pi-hole would query your router for local hostnames, and your router would forward any query it cannot answer itself to one of its upstreams.
If it forwards to Pi-hole, that would close a DNS loop, bouncing queries back and forth between Pi-hole and your router forever, or until time-out.
In such a constellation, a time-out would likely indicate that your router doesn't know any DNS records for your local hostnames.
Switching your router to use its defaults for upstream DNS would avoid such a loop.
I'd then expect your router to answer requests for local hostnames with
NXDOMAIN, proving it doesn't register DNS records for its DHCP clients.