It is narrated from Ali (may Allah be pleased with him) that he gave the verdict regarding a woman who married during her waiting period (iddah) that the two should be separated (i.e., the marriage should be annulled), and due to having relations with the woman, she is entitled to her dowry (mahr). The waiting period (iddah) which the woman disrupted, she must complete, and she must also observe the waiting period for the second husband.
Hadith Referenceمسند الإمام الشافعي / كتاب العدد والسكنى والنفقات / 1299
Hadith Takhrijاسناده ضعیف اخرجه البيهقى 441/7 - وفى المعرفة السنن والآثار له (4680) ۔ وعبد الرزاق (10532) و ابن ابي شيبة (18786)۔