Contradiction with Acts 12:4
This verse describes Peter being kept in prison, whereas Acts 28:18 discusses being released after examination.
Acts 12:4: And when he had apprehended him, he put [him] in prison, and delivered [him] to four quaternions of soldiers to keep him; intending after Easter to bring him forth to the people. [Easter: Gr. Passover] [quaternions: a file of four soldiers]
Contradiction with Luke 23:24-25
Pilate agrees to the crowd's demand to crucify Jesus, in contrast to the release after review in Acts 28:18.
Luke 23:24-25: And Pilate gave sentence that it should be as they required. [gave...: or, assented]
Contradiction with Mark 15:15
Pilate releases Barabbas instead of examining and releasing an innocent, differing from the outcome in Acts 28:18.
Mark 15:15: And [so] Pilate, willing to content the people, released Barabbas unto them, and delivered Jesus, when he had scourged [him], to be crucified.
Contradiction with John 18:40
The crowd chooses Barabbas to be released rather than Jesus, who was innocent, contrasting with the release in Acts 28:18.
John 18:40: Then cried they all again, saying, Not this man, but Barabbas. Now Barabbas was a robber.