I've also checked if these two IP ranges are selected for all plans created and they are. I've also checked in PHPMyAdmin -> database "virtualizor" -> table "ips" and all of the IPs appear correctly.
I've also rebooted both nodes (master and slave) thinking that this may be some sort of cache or error, but nothing changed.
I have to mention that those IPs that are missing (from 192.168.17.171 to 192.168.17.190) can't be allocated on either of the two nodes (master and slave).
What other info can I provide to get this fixed or to get a pointer in the right direction?