Mormon’s sequencing is confusing at this point. In verse 14 we have the children speaking under the influence of the Spirit, and then in 15 the ascension after the second day. Then Jesus returns, and in verse 16 we have the children speaking. Are there two incidents of the children speaking? Probably not. Mormon has been giving a summation, and in this case began summarizing an event that occurred chronologically on the day after his most recent text. At some point in writing he understood that he might be confusing the chronology, and he straightens it out. Verse 14 is a reference to the same event as verse 16, and they come on the third day of the Savior’s visit.