Many ProxySQL graphs are empty for proxysql2

Reproducable:

• set up 3 node PXC (mysql1, mysql2, mysql3)
• install pmm2, sysbench, proxysql2 on 'app' server
• configure pmm-client on appropriate machines, (add mysql, add proxysql)
• add pxc servers like this to proxysql:

  INSERT INTO mysql_servers  (hostgroup_id, hostname, weight) VALUES  (2, '<Internal_IP_mysql3>', 1000),  (3, '<Internal_IP_mysql1>', 1000),  (3, '<Internal_IP_mysql2>', 1000),  (3, '<Internal_IP_mysql3>', 1000),  (4, '<Internal_IP_mysql1>', 1000),  (4, '<Internal_IP_mysql2>', 1000);
  
  -- 2 is WRITER, 3 is READER, 4 is BACKUP_WRITER
  
  INSERT INTO mysql_users (username, password,default_hostgroup) VALUES ('sbuser', 'sbPass1234#', 2);
  
  INSERT INTO mysql_query_rules (rule_id, active, match_digest,destination_hostgroup, apply) VALUES (100, 1, '^SELECT.*FOR UPDATE', 2, 1);
  
  INSERT INTO mysql_query_rules (rule_id, active, match_digest, destination_hostgroup, apply) VALUES (101, 1, '^SELECT', 3, 1);

• LOAD/SAVE rules
• run sysbench oltp, pointing to proxysql
• wait X minutes for load
• open PMM2 on app. navigate to ProxySQL Instance Summary
• no matter which hostgroup you select, you always see the same data and many graphs not populated. see screenshots
• this should not be related to pmm2 as none of the stats tables changed