default-error-02. What is it?

[OGoodness]

I can't seem to track down what this error means, or what this request actually is.
Cause when I replicate what it says the request is in burp, I don't get the same result

[j3ssie]

That's mean built-in regex for passive detection matched.
You can look at it detail from here https://github.com/jaeles-project/jaeles/blob/master/core/passive.go#L126

The reason you're not get the same result from Burp because Burp Unpack gzip by default so it might happen in some target.