If you listen to the tenor saxophone and trombone together, they’re playing the same melody as the piano plays, earlier on in the song. But if you listen carefully, or look at the waveforms on the Explorer close-up, they’re not playing the same thing together.
But at two points in this passage, they play the melody together – each point is at the end of a four-bar phrase. What Jason’s doing is to bring together two untidy parts into one stronger part at the end of the phrase, giving a sense of direction towards the end of each phrase.