3,424. Was the Produce Sold Tithed or Untithed?

Hilchos Maaser 6:7

Let’s say that one person sold produce to another but he subsequently remembered that it was untithed. He ran to find the buyer so he could take the necessary tithes, but he couldn’t find him. If he knows that the produce no longer exists because it was already lost or eaten, then he doesn’t have to take tithes for it; if there’s a doubt as to whether or not it still exists, then he must take tithes for it from other produce.

Hilchos Maaser 6:8

Let’s say that someone sells produce. The seller claims that he sold the produce with the understanding that it was untithed, but the buyer claims that he agreed to buy tithed produce. In such a case, the seller must take the appropriate tithes as a penalty for selling untithed produce.