There should be overflow from B2 to B3 between iterations. Instead, B2 gets full and then the remaining passengers are "disappeared".
Remedies tried:
- decreasing dispersion parameter down to 0.2 [ doesn't work ]
- decreasing transfer and walk access distance to make sure they "make the bus" [ doesn't work ]
- made the bus depart and arrive 2 minutes earlier [ WORKS - but why? ]