when changing zabbix active agent hostname, old host keeps working on zabbix server

[iantmn]

We use a system with auto registration and when I change a zabbix active agent hostname in the config file, a new host is created with the new name as expected. However the old host in zabbix server (with the old hostname) still works, even though all documentation points towards the requirement for the hostname on the server and agent to be the same.

Does anybody know why this is happening?

zabbix agent 2 version: 6.4.5
zabbig server version: 6.4.5