Steps to reproduce:

1. Create host and 2 items (count and role (int)), see attach zbx_export_hosts.xml;
2. Create a trigger: {test:count.diff()}=1 and {test:role.last()}=0 (PROBLEM event generation mode: multiple), see attach file test.xml
3. Create a test data in file send1.txt, send2.txt, send3.txt, send4.txt (see attach files)
4. Create a bash script (see attach file send.sh):

   zabbix_sender -z 127.0.0.1 -s test -i send1.txt
   sleep 10
   zabbix_sender -z 127.0.0.1 -s test -i send2.txt
   sleep 10
   zabbix_sender -z 127.0.0.1 -s test -i send3.txt
   sleep 10
   zabbix_sender -z 127.0.0.1 -s test -i send4.txt
   sleep 10
   zabbix_sender -z 127.0.0.1 -s test -i send4.txt
   sleep 10
   zabbix_sender -z 127.0.0.1 -s test -i send4.txt

1. See problems page for result

Result:
We see that the trigger fires several times, although the condition uses the AND condition and the data is received several times unchanged.

See screenshots.

Expected:
I expected the trigger to fire only 2 times on a given data stream, but it did fire 4 times.