getBarcodePNG sometimes adds % at the end

[pokhiii]

We are using this code to generate and save the barcode png image.

$barcodeIdentifier = 'box$123456$'
$barcodeFormat = 'C39+';
$barcodeEncoded = DNS1D::getBarcodePNG($barcodeIdentifier, $barcodeFormat);
$barcode = base64_decode($barcodeEncoded);

$this->entity
             ->addMediaFromString($barcode)
            ->usingFileName('identifier.png')
            ->toMediaCollection('barcodes');

When we scan it back it returns box$123456$%