Discovery rule - item prototype to get values for different users

[jarleler]

Hi all, I am struggling to get values into the items for an discovery rule I have in Zabbix. The users are discovered but it doesn't look like values are created for the different macros. I believe there might be an issue with my jsonpath preprocessing.
The setup is like this:

1. Main item that gets the users/data from a JSON data structure:
Name: User Quota JSON
Type: Zabbix agent
Key: captive.portal.data
Data: Text

This item correctly gets json data from the agent and it looks like this:
[
{
"{#USERNAME}": "laptop",
"{#CURRENTPERIOD}": "weekly",
"{#USAGEDAILY}": 0,
"{#USAGEWEEKLY}": 9671900711,
"{#USAGEMONTHLY}": 0,
"{#USAGEUNL}": 0,
"{#QUOTADAILY}": 0,
"{#QUOTAWEEKLY}": "12288",
"{#QUOTAMONTHLY}": 0,
"{#QUOTAUNL}": 0
},
{
"{#USERNAME}": "mini",
"{#CURRENTPERIOD}": "weekly",
"{#USAGEDAILY}": 0,
"{#USAGEWEEKLY}": 0,
"{#USAGEMONTHLY}": 0,
"{#USAGEUNL}": 0,
"{#QUOTADAILY}": 0,
"{#QUOTAWEEKLY}": "1",
"{#QUOTAMONTHLY}": 0,
"{#QUOTAUNL}": 0
}
]

2. Then I have a discovery rule like this:
Name: User Quota Discovery
Type: Dependent Item
Key: captive.portal.discovery
Master Item: User Quota JSON (the main item from "1")
Preprocessing: JSONPath parameter: $[*]

3. For the discovery rule I am testing now with one item prototype like this:
Name: Quota Weekly for {#USERNAME}
Type: Dependent item
Key: captive.portal.quotaweekly[{#USERNAME}]
Master Item: User Quota JSON
Preprosessing JSONPath: $[?(@['{#USERNAME}'] == '{#USERNAME}')]['{#QUOTAWEEKLY}']

I am not able to get any values into the different macros.

Can anyone see what I am doing wrong?