Hm, I don't really {sutra je jipci je mencre} (but thanks for the compliment!), and I'm still not sure what to make of this. But it seems to me that {ti blanu je zdani} is *not* a good example sentence in the reference grammar.
(Since 'the x2 of a one-place brivla' is a separate issue, separately discussed, that need not distract us here, I'll stick to the {sutra je jipci} example.)
la gejyspa ku cusku di'e
> "mi sutra je jipci" is a perfectly fine sentence to say
I agree that 'I am fast, and a chicken' is what that sentence is probably supposed to mean, and what will be understood by a co-operative listener. But then, the speaker should have said {mi sutra gi'e jipci} or so. I don't think {mi sutra je jipci} makes sense. If it did, that would mean that places could be pragmatically cancelled out/filled with {zi'o} … or {no da}, whatever. But I think a legitimate Lojbanic reaction (besides {ki'a}) to {mi sutra je jipci} would always be {sutra je jipci ma}—the second argument is still there and can always be made explicit. Otherwise, we'd end up with place structure ambiguity in ellipsis sentences, wouldn't we?
My tentative conclusion is that CLL #12.12 might better be listed as an erratum. Opinions?