Fatal exception while removing duplicate strings from a list

Basically one function of my app should get an array with different strings from Firestore. Then another function should select 3 different strings from that array and store it in a list. The strings should not be identical, so in the end the list should have 3 unique random strings from the array I got from Firestore.

To achieve this I have the code below (which unfortunately I did not write by myself). Most of the times this code works fine, but sometimes I don't get any value. So as I said sometimes I get this error, which points me to the removeDuplicatesmethod:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.android.guessit, PID: 30272
    java.lang.IndexOutOfBoundsException: Index: 2, Size: 2
        at java.util.ArrayList.get(ArrayList.java:437)
        at com.example.android.guessit.GameFlow.SecondRound.FragmentCategory_2.removeDuplicates(FragmentCategory_2.java:767)
        at com.example.android.guessit.GameFlow.SecondRound.FragmentCategory_2.access$100(FragmentCategory_2.java:49)
        at com.example.android.guessit.GameFlow.SecondRound.FragmentCategory_2$1.onComplete(FragmentCategory_2.java:99)
        at com.google.android.gms.tasks.zzj.run(Unknown Source:4)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:214)
        at android.app.ActivityThread.main(ActivityThread.java:7050)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:965)

Here is the Fragment where I use the function I explained. So basically the getRandomElementfunction gets a random string from the array I got from the database and puts it into a list, but before that the removeDuplicatesfunction checks whether the string is already in the list or not and removes it accordingly:

 @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {

...

        btnNavFragCat1.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                questionKeyRef.document(mTvCat1).get().addOnCompleteListener(new OnCompleteListener<DocumentSnapshot>() {
                    @Override
                    public void onComplete(@NonNull Task<DocumentSnapshot> task) {
                        if (task.isSuccessful()) {

                            DocumentSnapshot document = task.getResult();
                            List<String> questions = (List<String>) document.get("questions");

                            List<String> randomList = getRandomElement(questions, 6);

                            removeDuplicates(randomList);

                            viewModel.setCategory(mTvCat1);

                            category.put("category", mTvCat1);
                            setUpCategory();

                            setUpQuestions();
                        }
                    }
                });

            }
        });

...

    private void removeDuplicates(List<String> list) {
        int count = list.size();
        for (int i = 0; i < count; i++) {
            for (int j = i + 1; j < count; j++) {
                if (list.get(i).equals(list.get(j))) {
                    list.remove(j--);
                    count--;
                }
            }
        }

        query1 = list.get(0);
        query2 = list.get(1);
        query3 = list.get(2);

        Log.d("One", list.get(0));
        Log.d("Two", list.get(1));
        Log.d("Three", list.get(2));
    }

    private List<String> getRandomElement(List<String> list, int totalItems) {
        Random rand = new Random();
        List<String> newList = new ArrayList<>();
        for (int i = 0; i < totalItems; i++) {
            int randomIndex = rand.nextInt(list.size());
            newList.add(list.get(randomIndex));
        }
        return newList;
    }

...

I would very much appreciate any help and hope that someone can explain me the error and maybe give me a solution to this.