[BUG] Ships disappear from contruction queue

[Oneiron]

I have had several ships disappear from construction queues in wharfs. It seems that the longer the ship sits in the construction queue the higher the chance of it vanishing. When the ships disappear you don't get your money back. I have lost millions on this bug.

Edit: I am not running any mods. Using v. 1.50 english.

[Endeavour79]

Would be good if you could share an before and after save game.