Another interpretation: This ["Keep far from a false matter"] is a warning to a judge that he should not seat beside him an ignorant judge.
A Judge May Not Seat an Ignorant Judge Beside Him
Yalkut Shimoni on Torah 352:12
דָּבָר אַחֵר, הֲרֵי זוֹ אַזְהָרָה לַדַּיָּן שֶׁלֹּא יוֹשִׁיב אֶצְלוֹ דַּיָּן בּוּר.