Exception raised by Geant4 in FullSimLight when simulating tt-bar events from Pythia generator

When simulating tt-bar events from Pythia generator in FullSimLight with the ATLAS full geometry sqlite file, these exceptions are raised from Geant4 Navigator:

-------- WWWW ------- G4Exception-START -------- WWWW -------
*** G4Exception : GeomNav0003
      issued by : G4Navigator::GetGlobalExitNormal()
 WARNING> Expected normal-global-frame to be valid,  i.e. a unit vector!
  - but |normal|   = -nan  - and |normal|^2 = -nan
 which differs from 1.0 by -nan
   n = (-nan,-nan,-nan)
 Global point: (-569.2252511,-382.1543636,4203.934)
 Volume: LAr::EMEC::Pos::InnerWheel::Electrode
 Solid: LAr::EMEC::Pos::InnerWheel::Electrode, Type: LArInnerElecrodWheel

============================================================
   State of Navigator: 
The current state of G4Navigator is: 
  ValidExitNormal= 0
  ExitNormal     = (0,0,0)
  Exiting        = 1
  Entering       = 0
  BlockedPhysicalVolume= None
  BlockedReplicaNo     = -1
  LastStepWasZero      = 1

 Current Localpoint = (-569.22525,-382.15436,458.934)
 PreviousSftOrigin  = (-569.22525,-382.15436,4203.934)
 PreviousSafety     = 0
Current History: 
History depth=5
Level=[0]: Phys Name=[WorldLog] Type=[N]
Level=[1]: Phys Name=[LArEndcapPos] Type=[N]
Level=[2]: Phys Name=[LAr::Endcap::Cryostat::EmecHecLAr] Type=[N]
Level=[3]: Phys Name=[LAr::EMEC::Mother] Type=[N]
Level=[4]: Phys Name=[LAr::EMEC::Pos::InnerWheel] Type=[N]
Level=[5]: Phys Name=[LAr::EMEC::Pos::InnerWheel::Electrode] Type=[N]

============================================================
Value obtained from stored global-normal is not a unit vector.

*** This is just a warning message. ***
-------- WWWW -------- G4Exception-END --------- WWWW -------