As I reported on the mailing list, there is a bug with AliasInterceptor not handling the Parameter.Empty that is returned from HttpParameters.get(). Since HttpParameters.get() always returns a non-null value, the Evaluated object is treated as always being defined, which results in the empty value being set incorrectly on the stack.
The bug was originally introduced here:
The fix is easy; this code:
needs to be updated to:
This way, it ensures the Evaluated value is only defined when appropriate.