The 4.2 update of Google Panda was launched on 18th July 2015 and the release was extremely slow. However, according to the assumption of many, the 4.2 Panda update either reversed or saw a significant change about a month after its release.
Experts say they were aware that the release of this update would occur gradually over a few months and as time went on more pages on websites would be updated according to the revised Panda algorithm. Therefore, if your website was one of those being revised by the Panda update, you would see a minor and slow increment in search engine rankings over a period of a few weeks. However, after the 14th of August 2015, websites experiencing this gradual improvement stated that those benefits were completely erased within just a matter of 24 hours.
This was experienced by many websites and it surprised every webmaster that saw it happen. Unfortunately, when Google was questioned regarding this sudden change, they had no comments about it.