LXX Gen 43:12

καὶ τὸ ἀργύριον δισσὸν λάβετε ἐν ταῖς χερσὶν ὑμῶν· τὸ ἀργύριον τὸ ἀποστραφὲν ἐν τοῖς μαρσίπποις ὑμῶν ἀποστρέψατε μεθ’ ὑμῶν· μή ποτε ἀγνόημά ἐστιν.

Take double the silver with you so that you may return the silver that was put back into the mouths of your sacks. Perhaps it was a mistake.