In April 2018, Miller and teammate Lee Wallace were suspended by the club pending an internal investigation into an altercation with manager Murty, in the aftermath of the 2017–18 Scottish Cup semi-final which Rangers had lost 4–0 to Celtic. Miller was fined by Rangers and left the club at the end of his contract. Five months after the incident for which they were disciplined, Miller and Lee Wallace won an appeal at a SPFL tribunal against the action taken against them, with the expectation they would make a financial claim against Rangers for the fines imposed. Over his three spells at the club, he made 301 appearances in all competitions, scoring 116 goals.