when linking a template to a host, if host already has zabbix agent items, they are updated to have interface id of NULL (which is not correct).
this currently drives server crazy and it repeatedly claims that host is unreachable without giving any additional information.
to make things even worse, frontend shows interface as selected for these items...

1. frontend shouldn't do this when updating items;
2. maybe there should be some protection/assert in the frontend against this ?
3. server should provide better log entries and be smarter about such items (for example, single poller should report same host as unreachable 10 times at once...) - maybe log a warning and ignore those items ?
4. unittesting should verify that interface id is correctly set depending on item type after any operation that might have modified any items

keyword : interfaceid