Patch 12866d3f110 (26 Jul 2021) has introduced new MySQL connection parameters: TLS encryption. Thus items "mysql.db.size" and "mysql.replication.get_slave_status" now require 7 parameters, not 3 as it was before.
Issue is "DB MySQL by agent 2" template was not patched to comply with changed items' parameters. So, the latest version of template cannot work properly with zabbix-agent2 that has MySQL TLS encryption support
The fix is to add 4 empty parameters for TLS encryption to the items mentioned earlier.
Git patch is attached to this issue