iText x and y position of the text incorrect - pdf

Question

I have a huge PDF document (1600 pages) from which I kept only a part of it by printing some pages in Acrobat Reader.
I am reading the text using iText with the following code:
public void decode(File file) throws IOException {
PdfReader reader = new PdfReader(file.toURI().toURL());
int numberOfPages = reader.getNumberOfPages();
ProcessorListener listener = new ProcessorListener();
PdfContentStreamProcessor processor = new PdfContentStreamProcessor(listener);
for (int pageNumber = 1; pageNumber <= numberOfPages; pageNumber++) {
PdfDictionary resourcesDic = pageDic.getAsDict(PdfName.RESOURCES);
processor.processContent(ContentByteUtils.getContentBytesForPage(reader, pageNumber), resourcesDic);
}
}
and the processor:
public class ProcessorListener implements RenderListener {
private final PdfReader reader;
public ProcessorListener(PdfReader reader) {
this.reader = reader;
}
#Override
public void beginTextBlock() {
}
#Override
public void renderText(TextRenderInfo tri) {
String text = tri.getText();
double x = tri.getDescentLine().getBoundingRectange().getX();
double y = tri.getDescentLine().getBoundingRectange().getY();
System.out.println(text + " => x:" + x + " y:" + y);
}
#Override
public void endTextBlock() {
}
}
What I observe is that in my initial (huge) document, the x and y coordinates change depending on the text position, but in my smaller saved document the coordinates of all texts are almost always the same (x is very small and y is big), in my case, for example x is invariably smaller than 2, and y is always almost equal to 480.
What's the reason for this behavior? I only have this problem if I print my PDF document using Acrobat Reader, not when I am printing it using Edge for example. Also the resulting document is correctly shown in Acrobat Reader or Edge, which is the reason I think that the problem is in my code.