How To Read A Retraction, Number Fucktillion

A retraction was published today in Nature Structural & Molecular Biology that Comrade PhysioProf does not know how to interpret:

Retraction: Cocrystal structure of synaptobrevin-II bound to botulinum neurotoxin type B at 2.0 Å resolution
Michael A Hanson & Raymond C Stevens
In this paper, we described both the three-dimensional crystal structure of a botulinum toxin catalytic domain separated from the holotoxin (BoNT/B-LC, PDB 1F82) and a structure of the toxin catalytic domain in complex with a peptide (Sb2-BoNT/B-LC, PDB 1F83). The complex was later refined and deposited in the Protein Data Bank (PDB 3G94). The apo structure (PDB 1F82) remains valid. However, because of the lack of clear and continuous electron density for the peptide in the complex structure, the paper is being retracted. We apologize for any confusion this may have caused.

What the fuck does “because of the lack of clear and continuous electron density for the peptide in the complex structure, the paper is being retracted” mean? Any crystallomotherfuckinographers care to weigh in? Honest mistake? Fake data? Peer review FAIL? Wut?