switching to the next activity throws an error ro.vendor.df.effect.conflict

as soon as I switch from one activity to the next and then back, an error appears in LOGCAT. Can someone help me here? LOGCAT:

2021-01-19 19:59:24.592 2766-2766/com.example.logistikmeisterprfungsvorbereitung I/ngsvorbereitun: Late-enabling -Xcheck:jni
2021-01-19 19:59:24.604 2766-2766/com.example.logistikmeisterprfungsvorbereitung  E/ngsvorbereitun: Unknown bits set in runtime_flags: 0x8000
2021-01-19 19:59:24.705 2766-2766/com.example.logistikmeisterprfungsvorbereitung I/Perf:  Connecting to perf service.
2021-01-19 19:59:24.716 2766-2766/com.example.logistikmeisterprfungsvorbereitung I/FeatureParser:    can't find joyeuse.xml in assets/device_features/,it may be in /vendor/etc/device_features
 2021-01-19 19:59:24.723 2766-2766/com.example.logistikmeisterprfungsvorbereitung E/libc: Access denied finding property "ro.vendor.df.effect.conflict"
2021-01-19 19:59:24.709 2766-2766/com.example.logistikmeisterprfungsvorbereitung W/ngsvorbereitung: type=1400 audit(0.0:709884): avc: denied { read } for name="u:object_r:vendor_default_prop:s0" dev="tmpfs" ino=14011 scontext=u:r:untrusted_app:s0:c75,c257,c512,c768 tcontext=u:object_r:vendor_default_prop:s0 tclass=file permissive=0
2021-01-19 19:59:24.760 2766-2766/com.example.logistikmeisterprfungsvorbereitung D/ForceDarkHelper: updateByCheckExcludeList: pkg: com.example.logistikmeisterprfungsvorbereitung activity: com.example.logistikmeisterprfungsvorbereitung.Agb@4be9501
2021-01-19 19:59:24.762 2766-2766/com.example.logistikmeisterprfungsvorbereitung D/ForceDarkHelper: updateByCheckExcludeList: pkg: com.example.logistikmeisterprfungsvorbereitung activity: com.example.logistikmeisterprfungsvorbereitung.Agb@4be9501
2021-01-19 19:59:24.780 2766-2766/com.example.logistikmeisterprfungsvorbereitung W/ngsvorbereitun: Accessing hidden method Landroid/view/View;->computeFitSystemWindows(Landroid/graphics/Rect;Landroid/graphics/Rect;)Z (greylist, reflection, allowed)
2021-01-19 19:59:24.780 2766-2766/com.example.logistikmeisterprfungsvorbereitung     W/ngsvorbereitun: Accessing hidden 
method Landroid/view/ViewGroup;->makeOptionalFitsSystemWindows()V (greylist, reflection, allowed)
2021-01-19 19:59:24.786 2766-2766/com.example.logistikmeisterprfungsvorbereitung D/ForceDarkHelper: updateByCheckExcludeList: pkg: com.example.logistikmeisterprfungsvorbereitung activity: com.example.logistikmeisterprfungsvorbereitung.Agb@4be9501
2021-01-19 19:59:24.986 2766-2766/com.example.logistikmeisterprfungsvorbereitung D/ForceDarkHelper: updateByCheckExcludeList: pkg: com.example.logistikmeisterprfungsvorbereitung activity: com.example.logistikmeisterprfungsvorbereitung.Agb@4be9501
2021-01-19 19:59:24.990 2766-2766/com.example.logistikmeisterprfungsvorbereitung D/ForceDarkHelper: updateByCheckExcludeList: pkg: com.example.logistikmeisterprfungsvorbereitung activity: com.example.logistikmeisterprfungsvorbereitung.Agb@4be9501
2021-01-19 19:59:25.053 2766-2797/com.example.logistikmeisterprfungsvorbereitung I/AdrenoGLES: QUALCOMM build                   : ed77089, I0c4fc4bb0e
Build Date                       : 12/24/19
OpenGL ES Shader Compiler Version: EV031.27.05.03
Local Branch                     : 
Remote Branch                    : 
Remote Branch                    : 
Reconstruct Branch               : 
2021-01-19 19:59:25.053 2766-2797/com.example.logistikmeisterprfungsvorbereitung I/AdrenoGLES: Build Config                     : S P 8.0.12 AArch64
2021-01-19 19:59:25.056 2766-2797/com.example.logistikmeisterprfungsvorbereitung I/AdrenoGLES: PFP: 0x016ee187, ME: 0x00000000
2021-01-19 19:59:25.073 2766-2797/com.example.logistikmeisterprfungsvorbereitung W/Gralloc3: mapper 3.x is not supported

this is the first activity from where I switch to the second activity (AGB)

package com.example.logistikmeisterprfungsvorbereitung;



public class Begrusung extends AppCompatActivity {


TextView tw5,tw3,tw4,impressum, agb;
Button btn2;
MediaPlayer player;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_begrusung);

    tw5= (TextView)findViewById(R.id.textView5);
    tw3 = (TextView)findViewById(R.id.textView3);
    agb = (TextView)findViewById(R.id.agb);
    impressum = (TextView)findViewById(R.id.impressum);
    agb.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(getApplicationContext(), Agb.class);
            startActivity(intent);
        }
    });
    impressum.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(getApplicationContext(), Impressum.class);
            startActivity(intent);
        }
    });


    btn2 = (Button)findViewById(R.id.button2);
    btn2.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(getApplicationContext(),MainActivity.class);
            startActivity(intent);
            player.pause();
            finish();
        }
    });


}

@Override
protected void onStop() {
    super.onStop();

        if (player != null && player.isPlaying()){
            player.reset();

            player.stop();
            player.release();
            player =null;
        }
        super.onStop();
    }

@Override
protected void onResume() {

        player = MediaPlayer.create(this,R.raw.hintergrundmusik);
        player.start();
        player.setLooping(true);

    super.onResume();
}

}

and that is the second activity. As soon as I go back to the first one, the error message appears in LOGCAT

package com.example.logistikmeisterprfungsvorbereitung;

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

public class Agb extends AppCompatActivity {

TextView agbtext;
Button agbzuruck;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_agb2);

    agbtext = (TextView)findViewById(R.id.agbtext);
    agbzuruck = (Button)findViewById(R.id.agbzuruckbutton);
    agbzuruck.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(getApplicationContext(), Begrusung.class);
            startActivity(intent);
        }
    });

}

}