Does a divorce pronounced as "by triple divorce" take effect if a gift from the elder sister enters the house by mistake and unintentionally on the wife's part, or does it not take effect?

A gift transfers from the giver to the recipient by possession. Thus, the fruit became the property of your wife's middle sister as soon as her eldest sister gifted it to her. Consequently, your wife took the fruit as a gift from her middle sister and brought it into your home. Therefore, you have not broken your oath because the condition upon which it was contingent did not occur. And even if the fruit had belonged to the eldest sister, there would be no broken oath as long as your wife took it unknowingly.