im tring to applay mnar missing patter to a dataframe with this python code

        values = dataframe[column].unique()
        value = np.random.choice(values)

        index = dataframe[dataframe[column] == value].index
        n_rows_to_delate = int(len(dataframe) * missing_ratio)
        index_to_delate = np.random.choice(index, numero_righe_da_canellare, replace=True)

        index_to_delate.sort()

        dataframe.loc[index_to_delate, column] = np.nan

All works well until dataframe.loc.
I expect this function to delete all the indices in the index_to_delete list, but it only deletes some of them and I really can’t understand why. The column from which I’m trying to delete the data contains only 0 and 1.
thx