I know nothing about Maryland taxes but I'd guess it comes down to whether you were a resident of Maryland for the year. Eight weeks in Australia isn't going to do it. The first thing you need to do is determine if you were a Maryland resident, or not. That's pretty much a "facts and circumstances" situation.
On the other hand, there's another way to look at this. If you worked 8 weeks in Virginia while being a Maryland resident then you would even THINK that somehow being taxed by both the feds and the state was "double taxation." You'd only complain about that if both Virginia AND Maryland extracted their full tax on your earnings.
