Suspect the answer might be 'not a bug', but thought I'd report it anyway. Seems like production slots are being moved up very early, rather than giving the lines a chance to fill. Or there is some other strangeness going on. http://www.airwaysim.com/game/Aircraft/Production/View/90/
is the line for NAMCs in JA. Only 2 airlines have ordered, both made a single order of 40 planes. Both did it within 4 months of the plane being announced, more than 4 years before the first delivery. I'd expect that the 2nd airline to make an order would get all their planes one slot after the first airline, so when the first airline receives plane #40, the second airline has received 39 planes. But instead, when the first airline receives plane #40, the second airline only has 27.
First airline gets a steady stream, every 4th or 5th slot until production picks up, and then every 8th or 9th slot until the order is complete.
Second airline gets a much more disjointed stream, the gaps start 4-4-8-5-10-5-10-4-10. Starting from 22nd Aug 64, when production is at full speed, the gaps go 9-18-9-17-9-18-9-17-9-18-9-17-9-18. But once the first player's order is complete, the second order switches to every 9th slot.
Even though there is a lot of empty space to move orders back one slot, instead of the second player getting every 9th slot, with an order pushed back one slot if full, they're instead getting every 9th slot, with an order losing its slot entirely every third time.