G4ExtrudedSolid::DistanceToOut() in Geant4 10.4 contains a bug. The following line (#1285):

G4double pz = p.z() - z1 - z0;

should be corrected to:

G4double pz = p.z() - 0.5 * (z0 + z1);

Potentially the bug can be responsible for stuck tracks.

Hope this helps,
Evgueni