Dear Sujoy and Qinqing,
thank you very much for reporting this.
It turns out that setting the scoring region of the dummy DETECT card to a BLCKHOLE region is not enough. The energies deposited in the that region interferes with the user routine applying the Gaussian broadening.
To make it work, no particle should ever reach the dummy scoring region. The simplest would be to add a second outer BLCKHOLE region surrounding the whole geometry, and use that for scoring.
Cheers,
David