Android : Strange ToggleButton behavior inside ListView

I'm having a simple ListView filled with some test items:

private ArrayList<NearbyRestaurantListItem> getItems() {
    ArrayList<NearbyRestaurantListItem> items = new ArrayList<>();
    // ..
    items.add( new NearbyRestaurantListItem(null, "Item number " , "seven") );
    items.add( new NearbyRestaurantListItem(null, "Item number " , "eight") );
    items.add( new NearbyRestaurantListItem(null, "Item number " , "nine") );
    items.add( new NearbyRestaurantListItem(null, "Item number " , "ten") );
    // ..
    return items;
}

The thing is that these list items have a toggleable "favorite" button. The strange behavior I am talking about is that if I toggle a favorite button another button from another list item gets toggled too. It appears that the 6th toggle button from the pressed one gets toggled too and I have no idea why. Is it because the OnClickListener* classes are static? NearbyRestaurantListItem is inflated like this:

public View getView(int position, View convertView, ViewGroup parent) {

    NearbyRestaurantListItemViewHolder holder;
    if(convertView == null){
        convertView = mInflater.inflate(R.layout.listview_nearbylist_item, parent, false);
        holder = new NearbyRestaurantListItemViewHolder();
        holder.restaurantThumbnail = (ImageView) convertView.findViewById(R.id.restaurant_thumbnail);
        holder.restaurantName      = (TextView) convertView.findViewById(R.id.restaurant_name);
        holder.restaurantGenre     = (TextView) convertView.findViewById(R.id.restaurant_genre);
        holder.openingHours        = (TextView) convertView.findViewById(R.id.opening_hours);

        convertView.setTag(holder);
    } else {
        holder = (NearbyRestaurantListItemViewHolder) convertView.getTag();
    }

    holder.restaurantThumbnail.setImageDrawable(null);
    holder.restaurantName.setText(items.get(position).getRestaurantName());
    holder.restaurantGenre.setText(items.get(position).getRestaurantGenre());
    holder.openingHours.setText("08:00 - 18:00 Uhr");

    if(holder.restaurantGenre.getText().length() == 0) {
        holder.restaurantGenre.setVisibility(View.GONE);
    }

    ToggleButton favorite = (ToggleButton)convertView.findViewById(R.id.favorite);
    favorite.setOnClickListener(new NearbyRestaurantListFragment.OnClickFavoriteButtonListener(activity));
    favorite.setTag(convertView);

    ImageView map = (ImageView)convertView.findViewById(R.id.map);
    map.setOnClickListener(new NearbyRestaurantListFragment.OnClickMapButtonListener(activity));
    map.setTag(convertView);

    return convertView;
}

I really feel stupid asking this but I can't figure out the problem here.