If you meet apportionment rules (most commuters would not), then any allocation of W-2 income is done at the W-2 screen, in the federal section, not the allocation screens in the state program. That is, you have to use a workaround in TT to compensate for your employer's mistake in not doing the allocation when issuing the W-2.
"Massachusetts adopted a final version of the
previous emergency regulation which now says “all
compensation received for services performed by a
non-resident who, immediately prior to the
Massachusetts COVID-19 state of emergency was
an employee engaged in performing such services
in Massachusetts (emphasis added), and who is performing services
from a location outside Massachusetts due to a
Pandemic-Related Circumstance will continue to be
treated as Massachusetts source income subject to
personal income tax . . . and personal income tax
withholding.”
Reference: https://www.hodgsonruss.com/assets/htmldocuments/Telecommuting_5.22.20.pdf
