Hi, Vrenaut74. It sounds like when you changed it to a full year MA resident, the income went up for the state of MA. This is correct since typically the full year state will report the same income as federal. 

If the taxpayer lived in MA the full year, code the W-2 to MA and CA as indicated on the W-2. MA will pull all income since it is the full year. However, CA should only pull the CA W-2 as long as they are indicated a part year or nonresident screen 55.011, CA part year/nonresident info. Also in this screen, you can enter MA for the field Domicile in 2020 (Mandatory). 

The following article may help.

https://proconnect.intuit.com/community/form-w-2/help/allocating-w-2-wages-and-withholdings-for-mult...