Steps to reproduce:

mysql Ver 8.0.21

Database: zabbix :: CREATE DATABASE `zabbix` DEFAULT CHARACTER SET utf8 COLLATE utf8_bin 

Zabbix Server 5.0.13

1. Default configuration. Create a host with a name 'Training-VM-05', setup interface and PSK.
2. Setup autoregistration for the same host without deleting the previous, settings include adding new host to a host group "Training/servers", linking with template "Template Module Zabbix agent active"

Result:

Observe duplicates in hosts list:

Any modification of these hosts results in error: