Well, they claim to have made 500 changes last year, that could be construed as having gotten it wrong 499 times?
Regardless, they're admitting mistakes on their own blog where many are complaining. Sites they don't think should have been downgraded were in fact downgraded (their own words).
Google may fix the most obvious sites manually but they surely will not fix(or even hear from) them all, do you own one of those? I think "gotten it wrong" is quite accurate right now.