Dear geometry experts,

in CMS simulation with Physics List FTFP_BERT_EMY we have regular problem, which stops tracking and enable abort of CMS run. This problem is not seen with our default Physics List. This happens since Geant4 10.5 but a particular event happens with Geant4 10.5ref07:

e+ with energy about 7 MeV stack on a border of the main envelop of the CMS geometry.

   54   -35.31   -53.11    658.5  0.007189 0.000769    0.634       231                           CMSE msc
   55   -37.16   -56.38    671.3  0.007163   0.0261      135       245                           CMSE msc
   56   -37.68   -57.75    674.1  0.007159  0.00403     31.9       248                           CMSE Transportation
%MSG-w SimG4CoreApplication:  OscarMTProducer:g4SimHits  26-Aug-2019 17:00:17 CEST Run: 1 Event: 19
SimG4Exception caght! 
-------- EEEE ------- G4Exception-START -------- EEEE -------
*** G4Exception : GeomNav0003
      issued by : G4Navigator::ComputeStep()
Stuck Track: potential geometry or navigation problem.
  Track stuck, not moving for 25 steps.
  Current  phys volume: 'CMSE'
   - at position : (-413.6315273152043,-445.665372234611,6570.049669070449)
     in direction: (0.260944788544001,-0.5260912944434142,-0.8094045757484816)
    (local position: (-413.6315273152043,-445.665372234611,6570.049669070449))
    (local direction: (0.260944788544001,-0.5260912944434142,-0.8094045757484816)).
  Previous phys volume: 'CMSE'

  Likely geometry overlap - else navigation problem !
 Track *abandoned* due to excessive number of Zero steps. Event aborted. 


-------- EEEE -------- G4Exception-END --------- EEEE -------

cms2018 geometry is used. No overlap in OCMS( world) and CMSE (main envelop) are detected.

Vladimir