It revolves around the track I'll Still Love You (originally titled When Every Song Is Sung) written by George and given to Ringo who recorded it for Ringo's Rotogravure. George didn't make the sessions for the song and upon hearing the end didn't like it and so threatened a lawsuit which was ultimately settled out of court.
Answer 3 here has details and wiki has a sentence on it, using Keith Badman's The Beatles Diary Volume 2 as the source:
Harrison himself was "not pleased" with the result and took legal action against Starr, which was soon settled out of court. When appearing together on ITV's Aspel and Company in ...