Toast showing up twice in phyiscal device but only once in emulator / Android Java

I don't know if this is common or what. But I only have one Toast when it successfully deleted the data from Realtime Database

here's my code btw.

holder.btndel_stud.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                AlertDialog.Builder alert = new AlertDialog.Builder(context);
                alert.setTitle("Delete Student Record");
                alert.setMessage("Are you sure you want to delete");

                alert.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        final DatabaseReference databaseReference = FirebaseDatabase.getInstance().getReference("Users");
                        final String uniqueKey = addingStudentsArrayList.get(position).getUniqueid();
                        databaseReference.addValueEventListener(new ValueEventListener() {
                            @Override
                            public void onDataChange(@NonNull DataSnapshot snapshot) {
                                databaseReference.child(uniqueKey).removeValue().addOnCompleteListener(new OnCompleteListener<Void>() {
                                    @Override
                                    public void onComplete(@NonNull Task<Void> task) {
                                        if(task.isSuccessful()){
                                            Toast.makeText(context, "Student Account/Record has been deleted..", Toast.LENGTH_SHORT).show();
                                        }
                                        else {
                                            Toast.makeText(context, "Something went wrong...", Toast.LENGTH_SHORT).show();
                                        }
                                    }
                                });
                            }

                            @Override
                            public void onCancelled(@NonNull DatabaseError error) {
                                Toast.makeText(context, error.getMessage(), Toast.LENGTH_SHORT).show();
                            }
                        });
                    }
                });
                alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        Toast.makeText(context, "Cancelled", Toast.LENGTH_SHORT).show();
                        dialog.dismiss();
                    }
                });
                alert.show();
            }
        });
    }

basically it toast twice on my mobile phone, even tho I called it only once. But yeah it toast once in my emulator. I genuinely don't know what's happening since there's no message indicating why it's toasting twice.

Toast.makeText(context, "Student Account/Record has been deleted..", Toast.LENGTH_SHORT).show();

The solutions I've tried: Reinstall the app on my phone, clear cache and clear storage but no luck. Thank you!