It's not really a bug. Think about it. If people REALLY needed to travel from A to B, and you're the only one on this route (my experimentation shows that this bug is only activated if you're the only one on the route), they have to pay anyways, so you can charge an impossibly high amount and you still get pax.
Of course, it's all exagerrated, but..
it's just a game

If you really think it's unfair, wait patiently till master Murphy fixes it, then suggest a reset.