has been ordered to appear in a Beverly Hills court on Friday for a progress report in her two DUI cases, a court spokeswoman confirms.
"The order for Ms. Lohan to appear is a routine thing for all DUI cases," court spokeswoman Vania Stuelp told PEOPLE on Thursday. "We're expecting her to be present [Friday] for a progress report."
A law enforcement source tells PEOPLE, "It's not that Lohan failed a drug test or anything, but it's an issue with her alcohol education program. It's all up to the judge Friday to determine what's going to happen to her. The judge could extend her probation for another year."
Lohan's attorney, Shawn Chapman Holley, wasn't immediately available for comment.
According to court records, as of July, Lohan, 23, has been successfully following her probation, which includes strict attendance in an alcohol education class.
Lohan was sentenced to three years' probation for her second DUI conviction
in August 2007.
Earlier this year, the court issued an arrest warrant
for Lohan, which stemmed from a misunderstanding and was later dismissed.