The most convenient way to observe the problem is to execute the "Zabbix stats cluster" item that belongs to the "Zabbix server health" template and check update records for item_tag table in zabbix_server.log (in debug mode). This item triggers the "High availability cluster node discovery" LLD, that in its turn discovers and then checks the following items:
"Cluster node []: Address"
"Cluster node []: Last access age"
"Cluster node []: Las access time"

As result, each time a value is returned for the master item ("Zabbix stats cluster"), item tags of the corresponding discovered items are updated:

101824:20220601:150516.096 query [txnlev:1] [select null from hosts where hostid=10084 for update]
101824:20220601:150516.097 End of DBlock_record():SUCCEED
101824:20220601:150516.097 query [txnlev:1] [update item_tag set tag='node-id',value='cl3tykf3k0001qm7puazcmw9w' where itemtagid=33643;
update item_tag set tag='node-name',value='' where itemtagid=33644;
update item_tag set tag='component',value='cluster' where itemtagid=33645;
update item_tag set tag='node-id',value='cl3tykf3k0001qm7puazcmw9w' where itemtagid=33646;
update item_tag set tag='node-name',value='' where itemtagid=33647;
update item_tag set tag='component',value='cluster' where itemtagid=33648;
update item_tag set tag='node-id',value='cl3tykf3k0001qm7puazcmw9w' where itemtagid=33649;
update item_tag set tag='component',value='cluster' where itemtagid=33651;
update item_tag set tag='node-id',value='cl3tykf3k0001qm7puazcmw9w' where itemtagid=33652;
update item_tag set tag='node-name',value='' where itemtagid=33653;
]
101824:20220601:150516.098 End of lld_items_tags_save() added:0 updated:10 removed:0

Currently this is not a big problem, but once ZBXNEXT-7554 gets merged, this will add multiple useless records in the changelog table.

Steps to reproduce:

1. Open the default zabbix installation
2. Open the list of items of Zabbix server host
3. Execute item "Zabbix stats cluster"
4. Make sure that "Cluster node ..." items are discovered
5. Execute the master item again
6. Check Zabbix server log (DebugLevel = 4)

Result: each time the master item is triggered, discovered item tags are updated
Expected: discovered item tags should be updated only when something is actually changed.

Server log: zabbix_server.log