A recent change in accounting rules will see some deaths previously accounted as unrealted to COVID listed as COVID deaths, whereas others previously listed as caused by COVID to be attributed as other causes. The new inclusions appear to mostly be those that were discovered through correlation of medical records which points to COVID being a severe infection reasonably viewed as a cause of death. The cases struck from the rolls are primarily those died within 60 days of being diagnosed with COVID but with little to no evidence of the infection being severe enough to be a contributing factor in the death. The net effect is a reduction of the state's COVID death toll from 23,700 to about 20,000, or a reduction of about 15%.
Notable about this change is the lack of public discussion of the change. And what we should watch for is other changes of the same sort. That may come as an important component for constructing a truthful narrative of the pandemic.
References
COVID-19 deaths in Massachusetts to drop under new counting method
Associated Press, 11 March 2022