On Jul 12, 2013, at 12:26 PM, Eli Zaretskii wrote:

>Maybe it is split, and then deleted, before we have a chance of
>displaying it?

I think that's exactly what's happening.  I did a long session of edebug
tracing and observed that behavior (split, then deleted).  I'm sorry that I
don't remember the details - it was quite a long spelunk through the Elisp.