9. Sheldon's "Soft Kitty" Song Ripping Off Another Song - The Big Bang Theory
Even the most casual fan of The Big Bang Theory will likely remember the "Soft Kitty" song that Sheldon's (Jim Parsons) mother would sing for him whenever he was sick.
The song ended up serving as a recurring gag throughout the series, enough that it eventually caught the attention of the heirs of late author Edith Newlin, who claimed that their mother's lyrics for the poem Soft Kitty, written for the 1937 children's book "Songs for the Nursery School," were used without permission.
Though the book's publishers, Willis Music, held that they retained the rights to Newlin's poem and licensed them to the show, Newlin's children contested that they in fact owned the rights, which were licensed without permission by Willis Music for not only the TV show but peripheral Big Bang Theory merchandise.
A lawsuit against CBS was initiated in 2015, and in 2017 a judge ruled against the Newlin family, citing that though Willis Music renewed their copyright for the book in 1964, this did not also automatically renew the Newlins' own claim on the lyrics.