motu m2 Interface

Hey,

I hope this is the right place to ask this question..

so I got a new Motu M2 Interface about a month ago. Since then there are periodic buzzing sounds coming from the Headphone Amps at "random" times. Sometimes it runs 3 hours without a Problem and sometimes the buzzing happens twice in 5 minutes. Turning the Interface off and on again "fixes" the buzzing temporarily.