We found that Zabbix adds host even if another host with exact same name but different case is present.
E.g. ABCD.xyz.com is different than abcd.xyz.com for Zabbix. This I think is not correct.
I can understand the need to add utf8_bin while installation, especially from performance perspective. But in the process we are letting Zabbix to discover two hosts with exactly the same name.
It looks this is a bug and needs to be addressed.