Hi Shaun,
If you're still looking for help here, I'd love to help! I understand you want to obfuscate the custom attribute data, but I don't see any issues with your webhook so far, which tells me that the error might live in the custom attribute name or value which you've hidden. Are you able to share a little more of the data, but still changing the value to a dummy name?
If this is helpful, I was able to successfully log an array with this code below:
"attributes": [
{
"external_id" : external_id,
"test" : [123,456,789],
"test1" : ["123","456","789"]
}
]
Let me know if you have any questions!
Allan
