Steps to reproduce:

1. Add a host using SNMPv3 authPriv and verify that connection to host, SNMP is "Green" and can get values using test on an item or latest data shows data.
2. In Zabbix and on the host change the SNMPv3 authentication protocol and/or privacy protocol. For example change from MD5 to SHA256 and/or DES to AES128.
3. Observe that in Zabbix on the host SNMP turns "Red" and using the item test does not work.
4. Restarting the server service or if going through a proxy restarting the proxy service will fix the issue and SNMP will turn green and the item test will start working. 

Result:

1. Observe that in Zabbix on the host SNMP turns "Red" and using the item test does not work.
2. Tried the following without success, restarting host, waiting over 24 hours, issuing "sudo zabbix_proxy -R config_cache_reload" on the proxy, disable/re-enable host.

Expected:
That when changing the SNMPv3 parameters that the changes will work without restarting the server service or proxy service.