Negative values positron heating and neutron-photon transport simulations

Dear all,

checking the discussion in Photon heating, I also found negative values of positron in my simulations (version 0.13.0). Since I want to consider the contribution of photons in the heating deposition, i.e. photon heating/total heating, how could I proceed?
Indeed, taking into account that too much energy is given to photons, this fraction can result wrong.

Thanks in advance for your time.
Best regards,

Christian