Zabbix script item: Different result between TEST and EXECUTE NOW if MACRO used

Steps to reproduce:

1. Create new script item with:

Parameter:
ourdata : [{"domain":"oicts.com","port":"443","ip":"1.2.3.4"},{"domain":"nu.nl","port":"443","ip":"1.2.3.4"}]

2. Create script:

var params = JSON.parse(value);
return params.ourdata; 

Result:

When testing using the test button:

When executing the item itself:

Cannot execute script: SyntaxError: invalid json (at offset 24)
at [anon] (duktape.c:36563) internal
at parse () native strict preventsyield
at [anon] (function:1) preventsyield 

Expected:

Regardless of whether the script is correct or not: I expect the same result on TEST as on EXECUTE NOW (update interval)! Otherwise troubleshooting is almost impossible. The TEST states data is all good, but when executing why are there hidden errors/additional checks?