J3301 falls under the Unclassified Drug and Medicare requires the description in the NOC code description - this is why the claim is either denying or rejecting at the clearinghouse (Injection, triamcinolone acetonide, not otherwise specified, 10mg) - Medicare does not accepted HCFA but if billing HCFA this will go in Box 19 and Electronic - Because you stated Medicare of GA please refer to this link for the Loop and segment
https://www.palmettogba.com/palmetto/jjb.nsf/DID/AW8MMP6652 - Also just a note this is fall all Medicare jurisdiction for this J code - In my system I have this description Hard coded at the CPT so the description always goes out.