One rumor is that Coltrane was nodding out, Monk called his name, and he sprung to consciousness and played a great solo, but I've also seen this account questioned.
I always assumed that there was confusion about whether Hawk or Trane was to go next, but who knows. Also, as I recall Monk displaces the rhythm of the tune at the end of his solo and that may have caused a moment's confusion. The other thing that really grabbed me on that track was the way that Gigi starts his solo with a little two note lick which Monk immediately copies and then persists with like a dog with a bone. It gives you just a little sympathy with Miles wanting Monk to lay out when he soloed. I suspect you needed a steady nerve to keep your line going with such strong comping.
The issue is extensively discussed in Robin R D Kelley's biography of Monk. Kelley denies that Monk "comps" at all - rather he plays counter melodies to the soloist's efforts. He says Monk does nothing to show the soloist the way and quotes Charlie Rouse who says that if you don't already have a firm grasp of the changes when playing with Monk you're lost.