So the bug is basically that a review from a non-PPA package is also being shown for a PPA package of the same name. That probably shouldn't happen. The easiest way to prevent it from happening is just not to present, or allow, reviews for (non-Purchase) PPA packages at all.
This is semi-related to bug 766951, where reviews for the same package version on a different distribution series are being counted but not shown. In that case, they should be shown.)
So the bug is basically that a review from a non-PPA package is also being shown for a PPA package of the same name. That probably shouldn't happen. The easiest way to prevent it from happening is just not to present, or allow, reviews for (non-Purchase) PPA packages at all.
This is semi-related to bug 766951, where reviews for the same package version on a different distribution series are being counted but not shown. In that case, they should be shown.)