App restarting on play store open click

 <activity
            android:name=".activity.landingpage.LandingPageActivity"
            android:label="@string/app_name"
            android:launchMode="singleTop"
            android:screenOrientation="portrait"
            android:theme="@style/AppTheme.NoActionBar">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

So its simple. When i open my app from launcher icon, it opens.I go and click on launcher my app icon again it brings my application to the front again since its open.However, If I go to the play store and click open from there my app has two instances open. If you want an example how working, facebook has same issue .also another app fotmob has same issue i think.