The one in the master bath just started "leaking" recently and now my daughter reports the same problem in her bath. Is this just a part of their normal function or do they need to be replaced or possibly just adjusted?
In order to answer the question with any assurance I would have to know what you mean by "leaking." However I am willing to hazard the guess that the vacuum breaker is indeed operating as designed - that is to say it introduces air into the pipe/hose when a vacuum is induced. This would cause the water to flow, and water flows in whichever direction is easiest.