It seems the song “Uptown Funk” has come under scrutiny before for copyright infringement. There was a threat of a lawsuit that was never filed from a 1970’s group called Sequence that felt the song took from their music piece, “Funk You Up”.
According to Yahoo, Mars and Ronson were also forced to add two of the Gap Band’s members as songwriters to avoid another lawsuit because the cadence of “Uptown Funk” almost exactly matched their song "Oops! Upside Your Head".
It looks like lawsuits and this song are never-ending.