Incorrect SOA with slave DNS
When using slave DNS with ISPconfig 3, after DNS records are synced - SOA entries are not the same. Only 'rndc reload' command fix this issue and it must be issued on NS1. Furthermore, NS1 (primary) and NS2 (secondary) is both 'master' servers. Tutorial used to setup slave BIND: https://www.howtoforge.com/how-to-run-your-own-dns-servers-primary-and-secondary-with-ispconfig-3-debian-squeeze
SOA records after DNS sync should be the same on both servers. Also, NS2 (secodary) server should be 'slave', not 'master' as it is now.
Server OS: Debian Server OS version: 7.11 ISPConfig version: 3.1.13
named version: BIND 9.8.4-rpz2+rl005.12-P1
'rndc reload' on NS1