It is narrated from Ata that Ibn Abbas and Ibn al-Zubair (may Allah be pleased with them) said regarding a woman who has taken khul‘ and then her husband divorces her: "She does not need a divorce, because the husband has divorced one who is no longer his wife."
Hadith Referenceمسند الإمام الشافعي / كتاب عشرة النساء والإيلاء والخلع / 1236
Hadith Takhrijاسناده قوى ولا تضر عنعنة ابن جريج عن عطاء اخرجه البيهقي: 317/7 - وفي المعرفة السنن والآثار له (4400) - وعبدالرزاق (11772) وابن ابي شيبة (18488)۔
It is narrated from Ibn Abbas and Ibn Zubair (may Allah be pleased with them both) that they said: "A woman who has obtained khula should not be divorced during her waiting period, because now the husband has divorced her and she is no longer his wife."
Hadith Referenceمسند الإمام الشافعي / كتاب عشرة النساء والإيلاء والخلع / 1237