Regula Document Scanner showing Black screen before/after document scan process. - Android

Question

I have used Regula Document scanner SDK to scan documents and while scanning a particular document, Black screen shows for less than a half of second before/after scanning.

What might be the issue?

Code is as below:

if (Common.regulaPermissionsGranted(this@DocumentScanActivity)) {
      startCamera()
   } 

startCamera() method is as below:

 private fun startCamera() {
        if (Instance().isReady) {
            showScanner()
        }
    }

and below is the showSacnner() method:

fun showScanner() = Instance().showScanner(this, completion)

Below dependencies used:

implementation 'com.regula.documentreader.core:fullrfid:6.1.6513@aar'
implementation('com.regula.documentreader:api:6.1.6564@aar') {
    transitive = true
}