I would skip the Download Electronic File activity entirely and just use a stream reader to extract the file directly from the document in the SDK Script.

The following is an example of how to do that:

// Get bound entry as DocumentInfo object
DocumentInfo doc = (DocumentInfo)this.BoundEntryInfo;

// Set output path
string outputFile = @"\\hostname\C$\temp\test";

// Set result variable to detect errors/failure
bool docExported = false;

try {
    // Check for electronic document
    if(doc.IsElectronicDocument){
        // Get document extension
        string ext = doc.Extension;
        
        // Read eDoc and save to external location
        string mimeType = "";
        // You can use either file stream or memory stream depending on what you need to do
        //MemoryStream ms = new MemoryStream();
        FileStream fs = new FileStream(outputFile + "." + ext, FileMode.OpenOrCreate);
        using (LaserficheReadStream eDocStream = doc.ReadEdoc(out mimeType)){
            // Copy eDoc to the stream
            eDocStream.CopyTo(fs);
        }
        
        // Set success result
        docExported = true;
    }
    // If source document has no eDoc
    else{
        // handle "error"
    }
}
finally {
    // Track results token
    SetActivityTokenValue("DocExported",docExported);
}

Just make sure you add a reference to Laserfiche.DocumentServices and that your workflow service account has access to wherever you're trying to put the file.

NOTE: When testing it from the script editor it will run as you and use your permissions, so you might see different results when actually running it in the workflow.

Although it is possible to access the result file, those are stored to a temporary path and I've seen situations in which temporary resources like those are removed/lost before the script can actually run.