Steps to reproduce:

1. Apply the attached template to a host, it contains a dependent item with heartbeat preprocessing
2. Send valid data

zabbix_sender -z zabbix_server -s zabbix_host -k heartbeat -o "123" 

data gets recieved and processed properly

1. Send invalid data

zabbix_sender -z zabbix_server -s zabbix_host -k heartbeat -o "abc" 

heartbeat_dep becomes unsupported

1. Send valid data

zabbix_sender -z zabbix_server -s zabbix_host -k heartbeat -o "123" 

heartbeat_dep is still unsupported <- BUG

Result:

heartbeat_dep is still unsupported even with valid data
Expected:
heartbeat_dep becomes supported after sending valid data

Notes:
**

• Sending different valid data recovers the item -> heartbeat is causing the issue

zabbix_sender -z zabbix_server -s zabbix_host -k heartbeat -o "456" 

• Only dependent items seem to be affected, I wasn't able to reproduce the issue using other item types