Unexpected `select` result about enoki HOT 1 CLOSED

template <typename BSDFSample,
          typename Value = typename BSDFSample::Value,
          typename Spectrum = Spectrum<Value>>
Spectrum eval_impl(const BSDFSample &bs,
                   EMeasure measure,
                   const mask_t<Value> &/*active*/) const {
    // (...)
    Value n_dot_wi = Frame::cos_theta(bs.wi);
    Value n_dot_wo = Frame::cos_theta(bs.wo);

    auto reflectance = select((n_dot_wi <= 0.f) | (n_dot_wo <= 0.f),
                              Spectrum(0.f), Spectrum(m_reflectance));
    // Unexpected result here when Value is Float:
    // select() always returns Spectrum(m_reflectance). 

    return (math::InvPi * n_dot_wo) * reflectance;
}