I'm making bulk support beams (way more than 100, that fit on the ground), put them inside a raft on a large cart - using birchwood log and maplewood shaft (turns: unfinished birchwood support beam)
After all bunch is done, draging some to my inventory with other required parts.
Placing in a crafting window all beams from my inv. then start to add maplewood shafts - after first is added, the beam that is crafted getting eject from a crafting window, but 2 other action/shafts are queued and were executed.
Possible cause: switching a wood type of item, while crafting (not tested if using only one type of wood causing the problem too).