Fault being raised while executing a raise fault policy

[#1]

I have an issue where I am raising my own custom fault coming out of a Java Callout that sets a variable, jwt_isValid, if the fault occurs. The RaiseFault policy gets triggered, however upon execution, there is a fault while trying execute the RaiseFault policy which eventually gets handled by my default handler. I'd like to know why this second fault is occurring.

Here is the code for my preflow where it gets triggered:

            <Step>
                <Name>RaiseFault401InvalidToken</Name>
                <Condition>jwt_isValid="false"</Condition>
            </Step>

Here is the policy itself:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
<RaiseFault async="false" continueOnError="false" enabled="true" name="RaiseFault401InvalidToken">
    <DisplayName>RaiseFault.401InvalidToken</DisplayName>
    <Properties/>
    <FaultResponse>
        <Set>
            <Headers/>
            <Payload contentType="application/json" variablePrefix="@" variableSuffix="#">{"exceptions":[{"type": "E","code": "401","message": "Invalid Token","detail": "details"}]}</Payload>
            <StatusCode>401</StatusCode>
            <ReasonPhrase>Invalid Token</ReasonPhrase>
        </Set>
    </FaultResponse>
    <IgnoreUnresolvedVariables>true</IgnoreUnresolvedVariables>
</RaiseFault>

And here is the trace table output for the step when it fails:

Variables Read and Assigned
raisefault.failed	true
raisefault.RaiseFault401InvalidToken
apigee.edge.execution
messageid	*****_CVAHK7MOO_RouterProxy-10-46_2
Error Headers
Content-Type	Error Content
Body	Properties
action	ABORT
stepDefinition-async	false
internal	false
stepDefinition-type	raisefault
expression	(jwt_isValid equals "false")
type	RaiseFaultExecution
enforcement	request
stepDefinition-continueOnError	false
expressionResult	true
stepDefinition-displayName	RaiseFault.401InvalidToken
stepDefinition-name	RaiseFault401InvalidToken
stepDefinition-enabled	true
result	false
error	Raising fault. Fault name : RaiseFault401InvalidToken
type	ErrorPoint
state	PROXY_REQ_FLOW
error.class	com.apigee.kernel.exceptions.spi.UncheckedException
Identifier	fault