From the new 2018-2019 Undergraduate Calendar:
Effective September 1, 2018, students may repeat a course twice (i.e. attempt a course three times). Cross-listed courses count as attempts. Grades from every attempt will appear on the academic transcript. The Cumulative GPA will include only the grade earned on the most recent attempt. Units earned will be counted once toward the student’s program requirements, regardless of the number of times the course is repeated. Prior to September 1, 2018 the grades from all attempts are included in the GPA calculation.