The DOR claim is "If you would have reported to a MA office but for Covid WFH policies, you are still working in MA".
Sure but it's more complicated than that. One rule covered until 90 days after the emergency order ended - that said you can only apportion at the same rate as prior years. Another began in Sept of '21 that said, working remote due to covid doesn't count but they did not limit it based on prior years.
So many people could and did apportion historical days + Sep-Dec, provided that remote work wasn't cause covid. If your job changes, that matters too.
In my case the major bullshit was by any interpretation of MA tax law, of any year in recent history, they should have said I could apportion at my 2020 rate (which was my 2019 rate too). Instead they just tried to say I owed taxes like I was practically a resident.