Yes, Titleist's parent company Acushnet did sue Costco in regard to the Kirkland ball following Costco's original lawsuit lodged against Titleist! Costco's original legal argument was that their ball did not infringe upon Titleist's patents. This was eventually followed by the Titleist allegation after they had done some testing to show that in their opinion 10 patents had been infringed in the manufacture of the Kirkland ball and that Costco was indulging in false advertising with its claim that Kirkland Signature brands “meet or exceed the quality standards of leading national brands.” The lawsuits were eventually settled out of court.