Why are my factories missing maintenance goods?

[Microphage]

I am subsidizing two factories in a state, AND the trade screen shows that I am exporting both machine parts and cement.

Yet when I hover over the output icon on each factory, it is showing a reduced output due to missing maintenance goods, i.e. machine parts and cement.

Is there anything I've overlooked which could be an explanation for this? I don't see why the goods are missing. If I'm subsidizing, the factory should be able to afford whatever it needs, right? And the goods should be available; they shouldn't be exported if there's an internal buyer.

I'm playing Prussia and it's 1838, if that gives any clue.

 

[Poppis]

When you subsidize a factory you don't pay for it's input/maintenance goods. Instead if the factory is not making a profit, you pay the difference. So the factory still has to be able to afford all the goods on its own.

 

[KevinG]

It's just a bug. I've seen this happen with wildly profitable factories that I'm not subsidizing and that have more than enough machine parts/cement under my economy.

 

[Microphage]

That's a pretty big bug. What about cases where you're actually importing those goods and they're missing? How are you supposed to know whether the missing goods are due to your rank being too low, or whether it's "just a bug?" How can you make any decisions about what to do about it?