The "pillar of truth" is made up of fallible men so has and will make mistakes.
It's just not right to think it is incapable of some error.
“some error” that would have been some error, not understanding what baptism is. if they got that wrong, maybe they got the books of the Bible wrong, maybe they got the Trinity wrong, maybe they got the divinity of Jesus wrong......or maybe, just maybe, the pillar of truth is just that and it is your “mind” that is wrong. which is more likely?