Somewhat related is Bug #13419: DNS updates do not work unless foreman server uses the authoritative DNS server as it's nameserver in resolv.conf - Foreman. I that setting query_local_nameservers to true makes it query the resolver configured in /etc/resolv.conf.
IMHO we should drop this query on the Foreman side entirely and only rely on the Foreman Proxy, at least if a DNS proxy is configured.