I have a trigger expression which uses multiple JMX items from a queue in ActiveMQ in the evaluation (replaced the long mbean path with "QueueX" for the sake of brevity):

{host:jmx["QueueX",EnqueueCount].min(15m)}>50 and {host:jmx["QueueX",EnqueueCount].min(15m)}>1.5*{host:jmx["QueueX",DequeueCount].min(15m)} and {host:jmx["QueueX",Name].regexp(DL\.*Q)}=0

EnqueueCount and DequeueCount update every minute, while Name updates once an hour (and never changes - it's a prototype)

Every now and then I get PROBLEM events in Zabbix which last from 0 to 1 second:

When I look at the latest data, the data points all match to the seconds in the timestamps:

These happen with a fairly high frequency:

I am assuming the trigger expression evaluates to TRUE for a very brief period (milliseconds?) which generate these bogus events that immediately clear.