It is possible to pickup and drop a log close enough to a cabin under construction (maybe already built, too) that when you turn the log into either planks or blocks, they will be "inside" the cabin collision boundry -- and cannot be reached by the player. This results in an unreachable plank/block until the cabin is destroyed; then the offending planks/blocks can be removed from the construction site.
Not very serious since it's reversable, but still very odd behaviour. One possible solution would be to code it so the building checks if the item is a part of it's required materials; if it is, the material is added to the building. If not, the item is 'pushed' outside of the building.