Steps to reproduce:

1. Create host Testhost with item Testitem, with Discard unchanged with heartbeat = 2m
2. Create trigger for Testitem:
   1. count(/Testhost/Testitem,3m) = 1
   2. OK event generation = None
   3. PROBLEM event generation mode = Multiple
3. (Purpose is to trigger when the first value appears)
4. Use zabbix_sender to send a value to the item, see that trigger is activated
5. Within the two-minute discard window: go to the item and click Clear history and trends, and then use zabbix_sender again to send a value to the item

Result:

Trigger is not activated when the second value is sent.

Expected:

Since history and trends was deleted for the item, it is expected that the trigger is activated when the second zabbix_sender was run, as it is now the only value associated with the item as all previous values were deleted.