O Mother, Where Art Thou? - S6-E13
Factual error: It is stated that the Mayor is 56 and his mother was, upon her death, an organ (heart) donor. Assuming she was at least 15 when she had him, she was at least 70 when she died. Seventy is out of acceptable boundaries for organ donors, especially if the recipients were to be close to a decade younger. Recipients on waiting lists nearly always receive their organs from sudden death victims with the organ (heart) in a perfect condition. A 70-something woman's heart can not outweigh the risks of the procedure.
Yeah Baby! - S6-E6
Factual error: When Paul demonstrates his Portuguese, the subtitles read "My monkey needs a haircut," when the translation is actually "I feel very sick."