QR generator bug caused a warehouse barcode to scan as a different product

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A developer's barcode generator produced a Code 128 label for a warehouse bin, "BIN-7742-A", that was valid under the format spec. Two weeks after printing, the scanner returned the wrong item, almonds, because the leading character was read as a control code, shifting the decoding. The label was technically correct Code 128 but encoded a different string than intended. The developer fixed it by adding mod 103 checksum validation, refusing payloads that could be misread as control codes unless raw mode is explicitly requested, and exposing both encoded and decoded values in the API response. The episode underscores that a scannable barcode is not necessarily one that scans as the intended value.

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