GA is not one of the states that tax nonresident telecommuters.

GA employers are, however, required to withhold on wages paid to nonresidents for services rendered in GA if more than 5% or $5,000 of their wages are attributable to GA.  At the end of the day, however, as Susan explains, only GA-source wages (generally based on services performed within the state of GA) should be taxable.  Your client should make sure the proper withholding certificate is submitted to the GA employer to prevent this from recurring this year.