Hi,
If is there are at least 2 functions in the trigger expression where one is nodata() and another one is historical one (last(), find(),...) Zabbix recalculates trigger in ~ 30 sec when it appears in the cache (because of nodata()) and to check second part of the expression (last(), find(), ...) it searches value. If there is no data in the cache history syncer goes to DB to check if there is some. it will try to find in the lates (for example last 1 hour) data first, then takes older and bigger time periods to search
But if host\item is new -there is no data in DB as well. Also Zabbix has marker to 'recognize' that item is new in the cache - so these queries can not be run for such items