When the state Department of Unemployment first updated its employer contribution rates for 2021, Suzanne Murphy thought she spotted a mistake.The solvency fund assessment, one of several factors used to calculate a business owner’s unemployment insurance contribution rate, jumped from 0.58% to 9.23% for 2021. For Murphy, CEO of Unemployment Tax Control Associates in Springfield, that meant an employer contribution rate that’s twice as high and a tax increase of thousands of dollars....