NetworkManager & systemd-resloved: DHCP provided DNS server isn't used

Hello,

I am using NetworkManager (1.24.2) & systemd-resloved (245.6) in their default configuration.

/etc/resolv.conf is a symlink to /run/systemd/resolve/stub-resolv.conf

As it should, NetworkManager reports in the logs when it starts:

dns-mgr[0x55f2a8093240]: init: dns=systemd-resolved rc-manager=symlink, plugin=systemd-resolved

Which is what I want.

NetworkManager correctly picks-up the right DNS server from DHCP

NetworkManager[19709]: <info> [1593431290.2268] dhcp4 (enp0s13f0u3u3): option domain_name_servers => '192.168.199.1'

But it doesn't detect that there is a change with the running configuration:

dns-mgr: (device_ip_config_changed): queueing DNS updates (1)
dns-mgr: (device_ip_config_changed): DNS configuration did not change
dns-mgr: (device_ip_config_changed): no DNS changes to commit (0)

Therefore, systemd-resolved keeps on using the fallback DNS server:

$ systemd-resolve --status
Global
       LLMNR setting: yes                 
MulticastDNS setting: yes                 
  DNSOverTLS setting: no                  
      DNSSEC setting: no                  
    DNSSEC supported: no                  
  Current DNS Server: 8.8.8.8             
Fallback DNS Servers: 1.1.1.1             
                      9.9.9.10            
                      8.8.8.8             
                      2606:4700:4700::1111
                      2620:fe::10         
                      2001:4860:4860::8888
          DNSSEC NTA: 10.in-addr.arpa     
                      16.172.in-addr.arpa 
                      168.192.in-addr.arpa
                      17.172.in-addr.arpa 
                      18.172.in-addr.arpa 
                      19.172.in-addr.arpa 
                      20.172.in-addr.arpa 
                      21.172.in-addr.arpa 
                      22.172.in-addr.arpa 
                      23.172.in-addr.arpa 
                      24.172.in-addr.arpa 
                      25.172.in-addr.arpa 
                      26.172.in-addr.arpa 
                      27.172.in-addr.arpa 
                      28.172.in-addr.arpa 
                      29.172.in-addr.arpa 
                      30.172.in-addr.arpa 
                      31.172.in-addr.arpa 
                      corp                
                      d.f.ip6.arpa        
                      home                
                      internal            
                      intranet            
                      lan                 
                      local               
                      private             
                      test                

Link 12 (enp0s13f0u3u3)
      Current Scopes: LLMNR/IPv4 LLMNR/IPv6
DefaultRoute setting: no                   
       LLMNR setting: yes                  
MulticastDNS setting: no                   
  DNSOverTLS setting: no                   
      DNSSEC setting: no                   
    DNSSEC supported: no                   

Link 2 (wlp0s20f3)
      Current Scopes: LLMNR/IPv4 LLMNR/IPv6
DefaultRoute setting: no                   
       LLMNR setting: yes                  
MulticastDNS setting: no                   
  DNSOverTLS setting: no                   
      DNSSEC setting: no                   
    DNSSEC supported: no

Which https://www.dnsleaktest.com/ confirms.

If I manually set the DNS server for the interface with resolvectl, it works and the correct entries are reported in the status.