Steps to reproduce:

1. Create some item and trigger
2. Send some data to item and detect problem
3. Change item to do not keep history
4. Send some data to item and detect problem again

Zabbix still uses value cache to calculate trigger, and it seems the value will stay there until Zabbix server restart.
Even when sending any value which must not create a problem, it is ignored, value is colected from value cache and problem is detected

If the calue cache is empty, it will try to read the value from database, where it still may exist

This behavior is very confusing, it may detect problems using wrong values ,and additionaly these problems will never close.

Expected:

If item is not storing history, history syncer will not try to calculate triggers for this item using value cache