The file is wrong: it says it contains a file inside, and the file doesn't exist. When you open it in Excel it ignores the error and when you save it back it saves a correct file.
I'll see if we can add a workaround for this, but this is in the limit of what is a "corrupt" file and I am not sure it shouldn't be reported that the file is wrong. (as we currently do). And I am afraid that silently ignoring this could cause data loss in some cases where there has been actual corruption of the file.
I'll check it out and see if there is a way to fix this while still marking corrupt files as corrupt. I'll let you know.