This issue must deal with the situation that occurs due to housekeeper (ZBX-11426) and currently unknown (ZBX-11439) bugs.

There can be situation when trigger is in problem state, but there are no corresponding records in problem table. In this situation no event - recovery event links are generated and trigger value is not updated.

1) when processing normal recovery event (not created by correlation and coming from trigger with correlation_mode none) the trigger value must be updated, even if no event - recovery event links were created
2) when processing OK event a warning must be logged if trigger in problem state doesn't have problem records.