Currently (version 10.2.2.41) the pop3 & imap banner is default for all IPs configured on the same server. Even though, there may be different domains hosted on different IPs but the banner displayed on all, is that of the primary domain only.

It is requested that to properly host a domain other than the primary on a server, it's pop3 & imap banners should also be customizable like smtp banner per domain.