Contradiction with Proverbs 3:5
This verse advises trusting in the Lord and not leaning on one's own understanding, which can be seen as a contradiction to Paul's independent reception of the gospel in Galatians 1:16.
Proverbs 3:5: Trust in the LORD with all thine heart; and lean not unto thine own understanding.
Contradiction with Acts 15:2-3
These verses describe Paul consulting with others about the gospel, which contrasts with his claim in Galatians 1:16 of not conferring with flesh and blood after receiving his revelation.
Acts 15:2-3: When therefore Paul and Barnabas had no small dissension and disputation with them, they determined that Paul and Barnabas, and certain other of them, should go up to Jerusalem unto the apostles and elders about this question.
Contradiction with Titus 1:3
This verse suggests that the preaching of God's word was manifested through preaching, which can be viewed as contradicting the direct revelation to Paul mentioned in Galatians 1:16.
Titus 1:3: But hath in due times manifested his word through preaching, which is committed unto me according to the commandment of God our Saviour;