Sahih Muslim 572 f
This hadith has been reported by Mansur with the same chain of transwitters and he said:
" He should aim at what is according to him correct."
وَحَدَّثَنَاهُ يَحْيَى بْنُ يَحْيَى، أَخْبَرَنَا فُضَيْلُ بْنُ عِيَاضٍ، عَنْ مَنْصُورٍ، بِهَذَا الإِسْنَادِ وَقَالَ ‏
"‏ فَلْيَتَحَرَّ الَّذِي يُرَى أَنَّهُ الصَّوَابُ ‏"‏ ‏.‏