Steps to reproduce:

1. Enable  remote commands in agent config file
2. Create host 
   Host configuration as below:
   
3. Create item
   Item with key: "system.run[head -c 15777310 /dev/zero | tr '\0' 'A']"
   Item configuration as below:
   
4. Start Zabbix server with Agent 2

Result:

Zabbix is not collecting data for this Item. See screenshot:

Same behaviour for Agent1

Item status is enabled

Expected:

According to Zabbix documentation 2 Remote commands:

Starting with Zabbix agent 7.0, remote commands can also be executed on an agent that is operating in active mode. Zabbix agent - whether active or passive - should run on the remote host, and executes the commands in background.