Judge Patricia Schnegg disclosed results of the random drug test during Brown's latest probation review hearing on Monday (September 24), and reminded the singer to be conscious of his public profile during the sitting.
"You are not an average person sitting in a living room," Judge Schnegg is quoted as saying in the Los Angeles Times. "You are not only in the public eye, but you are on probation."
Brown told his probation officer that he had smoked the drug in California, but failed the test in Virginia, where he was undertaking community service.
The judge, who noted that Brown has a medicinal marijuana card from California, ordered that no further action was to be taken at this stage following the failed test on June 18, 2012. She explained that the singer had not been ordered to submit to mandatory drug testing as part of his probation.
However, Judge Schnegg did set a further probation review hearing for November 1, and asked for a supplemental probation report to be prepared.
Concerns were recently raised by prosecutors over how much community service Brown completed as part of his sentence for an attack on former girlfriend Rihanna.
Judge Schnegg also asked Brown to meet with his probation officers within the next three days to work out the discrepancy in community service hours between his attorney and prosecutors.
Brown's probation term was set at five years upon sentencing in August 2009.