That’s really odd that the Worcester main is a stand alone section of D1 which is otherwise in eastern ME
There's no rule that dispatching territories have to be contiguous, and it certainly wouldn't be the only instance on CSX where that was the case. It also may be an effort to more equally balance the workload between D1 and D2 (since D2 has to handle all of the MBTA activity between Lowell-Bleachery and between Lowell Jct-Haverhill).
The only thing that makes it "odd" is the idea that D1 and D2 are geographic regions. If you just think of them as "Dispatcher 1" and "Dispatcher 2", it's not so odd sounding.