John,
By your original post and the reference Lion gave
"KPMG NOTE: Beginning September 15, 2021, employees working remotely outside of Massachusetts should have wages reported and taxes withheld to the state where they are physically performing services. Employers will want to make sure they are registered for payroll in the states their employees are working remotely, and able to handle the complexity of compliance for a mobile workforce." the MA company is reporting correctly. To add another wrinkle, you stated he travels to MA for meetings. Is he performing any services while in MA? I would indeed check with the MA DOR and if a non-resident return is required, then file it with the credit to NC for taxes paid to MA. It would appear to be small amounts here.