$include in DNS record causes errors

When adding an $include “/path_to_additional_dns_record/additional.record”;

and the record in /path_to_additional_dns_record/additional.record contains:

subdomain.domain.com. IN A xxx.xxx.xxx.xxx

the records would look like:

$ttl 38400 domain.com. IN SOA ns1.domain-sites.com. root.ns1.domain-sites.com. ( 2016030704 10800 3600 1209600 38400 ) domain.com. IN NS ns1.domain-sites.com. domain.com. IN NS ns2.domain-sites.com. domain.com. IN A xxx.xxx.xxx.001 www.domain.com. IN A xxx.xxx.xxx.001 m.domain.com. IN A xxx.xxx.xxx.001 localhost.domain.com. IN A webmail.domain.com. IN A xxx.xxx.xxx.001 admin.domain.com. IN A xxx.xxx.xxx.001 domain.com. IN TXT "v=spf1 a mx a:domain.com ip4:xxx.xxx.xxx.001 ?all" somesub1.domain.com. IN A xxx.xxx.xxx.002 mail.domain.com. IN A xxx.xxx.xxx.001 domain.com. IN MX 5 mail.domain.com. somesub2.domain.com. IN A xxx.xxx.xxx.001 www.somesub2.domain.com. IN A xxx.xxx.xxx.001 ftp.somesub2.domain.com. IN A xxx.xxx.xxx.001 m.somesub2.domain.com. IN A xxx.xxx.xxx.001 localhost.somesub2.domain.com. IN A webmail.somesub2.domain.com. IN A xxx.xxx.xxx.001 admin.somesub2.domain.com. IN A xxx.xxx.xxx.001 autoconfig.domain.com. IN A xxx.xxx.xxx.001 _dmarc.domain.com. IN TXT "v=DMARC1; pct=100; ruf=mailto:postmaster@domain.com; rua=mailto:postmaster@domain.com; p=none" $include "/path_to_additional_dns_record/additional.record";

It gives me the following error:

Warning - errors were found in this domain's DNS records : This domain has email enabled, but none of the MX records point to it. Either the MX records should be corrected, or the email feature disabled if mail is hosted externally.

when I remove the $include, save and restart bind it is ok again.

Am I missing some?