If you're talking a few days a month probably no a big deal. I have a friend who did a 6 week voluntary assignment in addition to the other drops and he was talked to by his in base CP. He is spending less time at the unit and more at the airline till probation is over now...do what you got to do, but be as anonymous as possible till off your probationary status. You could fail Chuck Yeager on a checkride if you were looking to!