Thank you for contacting support.
We would like to request you to please try using below code snippet with Aspose.PDF for .NET 18.3 in your environment. We have attached generated file for your kind reference. BIB-DE000DGQ4425_18.3.zip
// Open document
Document pdfDocument = new Document(dataDir + "BIB-DE000DGQ4425.pdf");
// Create TextAbsorber object to extract text
//TextAbsorber textAbsorber = new TextAbsorber();
TextAbsorber textAbsorber = new TextAbsorber(new TextExtractionOptions(TextExtractionOptions.TextFormattingMode.MemorySaving));
// Accept the absorber for all the pages
// Get the extracted text
string extractedText = textAbsorber.Text;
// Create a writer and open the file
TextWriter tw = new StreamWriter(dataDir + "BIB-DE000DGQ4425_18.3.txt", false, System.Text.Encoding.UTF8);
// Write a line of text to the file
// Close the stream
In case you notice any problem, please share a screenshot highlighting the issue so that we may try to reproduce and investigate it in our environment.