Steps to reproduce:

1. Create host and http item schedule 24h
2. Try to trigger "execute now" via API with itemid created before

{    "jsonrpc": "2.0",    "method": "task.create",    "params": [        {            "type": 6,            "request": {                "itemid": "{ITEMID}"            }        }    ],    "id": 1} 

Result:
returns taskid. 
But nothing else happens. No execution and no result from task.get api
Expected:

execution of the item