Contradiction with Galatians 6:1
While 2 Corinthians 2:1 discusses not coming in heaviness, Galatians 6:1 emphasizes restoring someone with meekness if they are overtaken in a fault.
Galatians 6:1: Brethren, if a man be overtaken in a fault, ye which are spiritual, restore such an one in the spirit of meekness; considering thyself, lest thou also be tempted. [if: or, although]
Contradiction with Matthew 18:15
This verse advises going to someone directly if they have sinned against you, potentially creating a heavy confrontation, in contrast to Paul's aim to avoid heaviness in 2 Corinthians 2:1.
Matthew 18:15: Moreover if thy brother shall trespass against thee, go and tell him his fault between thee and him alone: if he shall hear thee, thou hast gained thy brother.
Contradiction with Proverbs 27:6
Faithful are the wounds of a friend; contradicting Paul's idea of avoiding heaviness by indicating that sometimes truth (which can be heavy) from a friend is necessary.
Proverbs 27:6: Faithful [are] the wounds of a friend; but the kisses of an enemy [are] deceitful. [deceitful: or, earnest, or, frequent]
Contradiction with James 5:19-20
Turning a sinner from the error of their way, possibly through confrontation, as opposed to avoiding heaviness.
James 5:19-20: Brethren, if any of you do err from the truth, and one convert him;