Using Hepmc3 as generator for O2 keeps freezing the simulations

Dear experts,

I am using hepmc as an event generator for O2. I run the command

o2-sim -j 1 -n 5000 -g hepmc -e TGeant4 --configKeyValues "HepMC.fileName=electrons.hepmc;HepMC.version=3;Diamond.position[2]=0.;Diamond.width[2]=5.6;SimCutParams.maxRTracking=300"

These hepmc files consist of 2 electrons per event and look like this per event

E 0 0 2
P 1 0 -11 -1.2699084281921387e+00 -4.1446438431739807e-01 2.5651476383209229e+00 2.8921327590942383e+00 1.1610261048342575e-03 1
P 2 0 11 1.2312363386154175e+00 3.9473712444305420e-01 3.0055606365203857e-01 1.3274390697479248e+00 4.6642744074515039e-04 1

Would anyone know why these simulations keep freezing? i.e. they get stuck at simulating one event, but this number is different every time. Sometimes it is at 2800, the other time it is at 4800 while using the same input.hepmc file

And sometimes, the event is completed, but it is terribly inconsistent and does not really give me a clue why it suddenly stopped.

It would be a great help if someone could point me in the right direction. If you require more information, please let me know and I will provide whatever you request.

Kind regards,