There are two things that come into play here:
(1) For those born on or before Nov. 1, 1955, and with income below a certain threshold ($87,200 Single, $109,050 Married Filing Jointly), the first $15,000 of many types of pension income (but not IRA income) is exempted from RI income tax. TurboTax should handle this automatically.
(2) RI has a progressive income tax which means that the tax rate on higher incomes is more than on lower incomes. For part-year and non-residents, it uses the unitary taxation method. In this approach, a tentative tax is first computed based on the taxpayer's total income, irrespective of where earned, and then multiplies it by the percentage of that income earned from RI sources.
Conclusion: taxpayer should not manually zero out their pension income as (1) covers what should be removed and (2) implies that manually zeroing may illegitimately reduce the rate at which the RI portion of income is taxed.
References:
https://tax.ri.gov/media/19126/download?language=en
https://tax.ri.gov/sites/g/files/xkgbur541/files/notice/Pub_2021_02_pension_income_guide_04_06_21.pd...
