Unable to fully close activity when using "singleTask" as launch mode

I'm trying to create a separate activity and use it to receive data from other applications. This SecondaryActivity is being launched through intent.action.SEND and android.intent.action.SEND_MULTIPLE in the manifest. I have also set it to use launchMode="singleTask" to avoid a duplicate app problem (if you keep selecting the app in the android share sheet and clicking back you can spin up multiple instances of the app).

launchMode="singleTask seems to work so far but I cannot get it to close even when adding finish() and finishAffinity() in onBackPressed(). When i look at the back stack, it says that SecondaryActivity is closed, but upon pressing the navigaton button, I can still see the activity.

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"
    android:supportsRtl="true"
    android:theme="@style/Theme.TestProject">
    <activity
        android:name=".MainActivity"
        android:exported="true">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />
            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity
        android:name=".SecondaryActivity"
        android:launchMode="singleTask"
        android:exported="true">
        <intent-filter>
            <action android:name="android.intent.action.SEND" />
            <action android:name="android.intent.action.SEND_MULTIPLE" />
            <category android:name="android.intent.category.DEFAULT" />
            <data android:mimeType="*/*" />
        </intent-filter>
    </activity>
</application>

My SecondActivity looks like this

class SecondaryActivity : AppCompatActivity() {
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_secondary)
    }
    override fun onBackPressed() {
        finish()
        finishAffinity()
    }
}

This problem happens when the app is completely closed and is launched through sharing a file. I cannot get the SecondaryActivity to not show up in the navigation screen even after closing it by pressing the back button. adb says there are no activities in the stack but i still see it in the navigation.

This is called Recents screen which is a system-level UI that lists recently accessed activities and tasks even if the application has finished.

If you don't want to see the app in the recent apps after pressing back button, using finishAndRemoveTask

override fun onBackPressed() {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
        finishAndRemoveTask()
    } else {
        finish()
    }
}