No. U.S. Citizenship and Immigration Services (USCIS) has been very clear that tax credits, including the Earned Income Tax Credit (EITC) and the Child Tax Credit (CTC), are not considered in the public charge assessment. This would also include the WFTC.
The Working Families Tax Credit statute similarly states that this program is not a public charge: “Receipt of the refund under this section may not be used in eligibility determinations for any state income support programs or in making public charge determinations.” Read the complete statute here: RCW 82.08.0206.