Comment 9 for bug 239499

Why do you say it doesn't fit the theory? IIRC we ran into this a long time ago in 'bzr' with one of Aaron's branches. He had some ghosts that we didn't have in bzr.dev. And so some of his inventories had different last-modified values for given file texts.

His delta patch was overlayed on a bzr.dev revision, which meant that when the text was extracted, the delta applied cleanly, but the final content sha1 sum did not match.

That certainly seems like what is happening here, as the failure is while extracting an inventory, that the full text sha1 sum doesn't match the saved value.