Did the Buddha break his promise?
Those are two sentences. Perhaps the first is the statement and the second the analysis.

Also in the Pali it's a single compound word:

Mendicants, I shall teach you the analysis of a recitation passage.
uddesavibhaṅgaṁ vo, bhikkhave, desessāmi.


uddesa

recitation, instruction; indication; brief indication, brief statement;
summary exposition instructing, specifying; inviting; food for a specific person



vibhaṅga
distribution; division; classification

So maybe there's no promise of a separate analysis -- it's just the word they use, like &quot;explanation&quot; or &quot;dhamma-talk&quot; or something like that, and this one happened to be a very short one.
Also I wonder whether uddesa is necessarily always verbal (apparently they often are, so often that one was expected) -- whether this might be a teaching-by-example instead of a verbal analysis.