CursorLoader doesn't update contents

I have a ContentProvider. There are my query and insert methods:

@Override
public Uri insert(Uri uri, ContentValues values) {
    final int match = sUriMatcher.match(uri);
    long id = -1;
    switch (match) {
        case ARTICLES_LIST:
            id = ArticlesDataSource.getInstance().addArticle(values);
            break;
    }

    Log.d(LOG_TAG, "Notify change for URI: " + uri);
    getContext().getContentResolver().notifyChange(uri, null);
    if (id != -1) {
        return ArticleContract.buildArticleWithIdUri(id);
    }
    return null;
}

and

 @Override
public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {

    final int match = sUriMatcher.match(uri);
    Cursor refCursor = null;
    switch (match) {

        case ARTICLES_LIST:
            refCursor = ArticlesDataSource.getInstance().getAllPreviewArticlesCursor(selectionArgs, selection, selectionArgs, sortOrder);
            break;

        case ARTICLES_LIST_BY_CATEGORY:
            Article.Category category = ArticleContract.getCategoryFromUri(uri);
            refCursor = ArticlesDataSource.getInstance().getPreviewArticlesCursorByCategory(selectionArgs, selection, selectionArgs, sortOrder, category);

            //Modify uri for correct listener behaviour. Full uri is: content://payspace.ssidit.pp.ua.payspacemagazine/articles/category/categoryName
            List<String> segments = uri.getPathSegments();
            String lastSegment = segments.get(segments.size() - 2);
            String uriStr = uri.toString();
            uri = Uri.parse(uriStr.substring(0, uriStr.indexOf(lastSegment) - 1));
            break;
        default:
            throw new UnsupportedOperationException("Unknwon uri: " + uri);
    }

    Log.d(LOG_TAG, "Registered for observe changes in uri: " + uri.toString());
    refCursor.setNotificationUri(getContext().getContentResolver(), uri);
    return refCursor;
}

My logs for notifyChange() and setNotificationUri():

Registered for observe changes in uri: content://payspace.ssidit.pp.ua.payspacemagazine/articles

Notify change for URI: content://payspace.ssidit.pp.ua.payspacemagazine/articles

As you can see, uris are equal. Content adds to the database. I don't close a cursor in my code. What can be wrong?