102% building mine entrance bug

[sunnyortego]

1. I enter some ingredients (boards and bricks)
2. click build
3. enter more ingredients (more boards and bricks)
4. click build. While building, it will take away 2 ingredients.

so far it's happened on the last 3 I built. first one I had all 30 boards and clicked build, then added the bricks clicked build and it took away 2 boards. The next 2 mine entrances I've done, it has taken away 2 bricks on each one the same way.

[Procne]

4. click build. While building, it will take away 2 ingredients.

What will take away those ingredients? From where?

[MagicManICT]

Been reported before, but the source of the problem hasn't been tracked down yet. I'm not sure if I can find that post, though.