The crafter seems to have issues when the bufffering item stack mode is set to single.
If there are multiple items in the crafter inventory and the mode is change, all items, beyond a single one in a slot, get ejected. Most seem to get ejected into the world but some I could find. In addition, anything beyond a single item in the output slot also gets ejected, which will have the craft start crafting a new batch, which in turn get ejected.
Either the mode change only alters the insertion of items, not allowing them to exceed a single one, but allowing any excess to remain, and craft up to a full stack in the output buffer. This is how it seemed to work previously.
Keep the current ejection feature for the input slots, but not the output slot, and only allow one crafting operation to occur when the output slot is empty.