Yes, it should be SC exempt.
But if the SC state amount ended up being a small $$ amount, the change may not have been enough to affect the actual SC tax assessed.
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And a side note, in case you are overworking, you only break out the SC $$ and any US territories (like Puerto Rico, Guam etc)....the remainder is lumped together a "More than one state" (or Multiple States if you are using Online software).
Example for an NC resident: