My understanding (from the wrong side of the Potomac):

On days when she goes to the MD office, she has MD source income and reports it on her MD NR tax return.  If that's 0 days, then it's all MA source.

But let's see if my MD peeps agree:

@sjrcpa @dascpa 

I agree, the announcement makes no sense.  How can someone live in DE but telework from MD?  Panera Bread maybe? 🙂