Is the criterion what the narrator reported, not what he saw?

The Shaykh : And so, among the principles and rules in which the majority differed from the Hanafis is this: if a hadith is marfu' (traced to the Prophet) from a Companion, traced back to the Prophet (peace and blessings be upon him), and then an opinion from this Companion comes that contradicts his narration, is the criterion then his narration or his opinion?
The narration. But the Hanafis said: No, the criterion is his opinion, not his narration. So this rule also must be placed before us when we want to address a disputed issue among the Companions, let alone one that is disputed among those who came after them.