Issues with focus and sharpness

Hello people! I’m new to Negative Lab Pro and I really like it; it gives me a lot of freedom and has revolutionized my workflow. However, I have a problem and I’m asking you for help. When I got the negatives scanned back from the lab or doing them by myself with my Epson V800 scanner, I find the photos to be sharp and clear. But when I do the positive-to-negative conversion in Negative Lab Pro, the pupils and details are completely lost. How is this possible? I’ll attach an example for you. Can anyone help me? Thank you.