This update was reported by website owners and SEOs but wasn’t officially confirmed by Google. It was released as part of the ongoing penguin 3.X rollout, and appears to be an additional adjustment “refresh”, gradually released by Google after the penguin 3.0 update which have caused many issues. As with any penguin update, this update’s purpose is to address website over-optimization as well as inbound link issues.
Regarding this update specifically, many have reported that previously observed changes made by the Penguin 3.3 update have reverted back to the earlier ranking state of Penguin 3.2.
Much like the other penguin 3.X updates, this update was observed by website owners and was never officially confirmed by Google, there’s no information on the percentage of affected queries.