DefaultFaultRule in proxy endpoint, executing after faults in target endpoint

[Edsasto]

Hi, I have implemented a defaultFaultRule in my proxy endpoint as follows 

<DefaultFaultRule>
    <Step>
        <Name>AM-ErrorMessage/Name>
    </Step>
    <AlwaysEnforce>true</AlwaysEnforce>
</DefaultFaultRule>

I've noticed that when the alwaysenforce element is set to true, this condition is evaluated even if the error occurred at the target endpoint, when alwaysenforce is false it is not evaluated if the error comes from the target endpoint.

It does not make sense to me that the faultRules defined in the proxy endpoint are executed in the target endpoint so I would like to know if this behavior is due to a bug or it is an expected behavior, thank you in advance.