Usually, SVU does a pretty good job at keeping score on the accurate ages, anniversaries, patnerships, and so on. In season 6, Kathleen was 17 years old when she was picked up for DUI.
But in season 8, Kathleen was still 17 years old rather than the correct age of 18! If the writers were re-writing history, Kathleen would've been 15 when she was first arrested for drunk driving. That is not legal as 15 years old is a learner's permit age and wouldn't have been able to drive at night (at least, that's the laws in my state are). Viewers have noticed the age blooper, but SVU never corrected.
The following season, Kathleen started in college and in season 10, Kathleen was 19 years old when she should've really been 21.