I was shocked to find packages labeled "potato leaves" for sale at the local big Asian market. I had always thought that the only edible part of the potato plant is the starchy tuber and that all other parts--stems, leaves, roots--are highly poisonous. Turns out I was right, but that sweet potato leaves are edible and this is likely what I saw on sale. Or it could be something else entirely that got "potato" attached to it in some Asian language, just as what is called "yam" in English is a variety of sweet potato and nothing to do with true yams.
Could be a deadly language error to confuse sweet potato leaves with the leaves of the true potato.
-Paul W.