Using lighthouse node module getting very high LCP value for the page compare to measuring it through chrome add on

Question

I am using the lighthouse node module to measure the performance of my application pages. I have written a small node script that would use this module to measure the performance of the multiple pages of my application. To run the script with the user session I am first opening the Chrome instance in a debug mode and then with the app URL I am establishing the user session and further using the port I am running the script with the CLI command to measure the performance of the application. The function code is as follows

function runLighthouse(url, pageName) {
  return new Promise((resolve, reject) => {
    const reportPath = `report-${encodeURIComponent(pageName)}.html`;
    const chromeFlags = `--window-size=1920,1080`; // Adjust the viewport size as needed
    const lighthouseProcess = spawn('lighthouse', [
      url,
      '--output=html',
      '--only-categories=performance',
      '--port',
      port,
      '--chrome-flags',
      chromeFlags,
      '--max-wait-for-load=60000',
      `--output-path=${reportPath}`
    ]);
   lighthouseProcess.stdout.on('data', (data) => {});

    lighthouseProcess.stderr.on('data', (data) => {
      const errorOutput = data.toString();
      console.error(`Lighthouse measurement error: ${errorOutput}`);
    });

    lighthouseProcess.on('close', (code) => {
      if (code === 0) {
        console.log(`Lighthouse measurement completed for ${pageName}`);
        resolve(reportPath); // Resolve with the path of the HTML report
      } else {
        console.error(`Lighthouse measurement failed for ${pageName}`);
        reject(new Error(`Lighthouse process exited with code ${code}`));
      }
    });
  })

Now the issue I am facing with this is The LCP reading I am getting in the HTML report is very high compared to when I measure the same using the lighthouse tool. I am not sure through script why that reading is too high.