With the latest update of the play Google Store, Google has fixed a strange and rather annoying bug that “mixed” downloaded applications with those of third parties. Previously, third-party applications, installed via manually. Apk were seen as the Play Store bought or downloaded from the market.
The problem itself was not so serious, it became annoying when the Store update blocked the application or even prevented it from reinstalling itself with Play Store, this is because the software was already belong to us but it was not possible to re-download it because paid for.
Personally, I never had this problem and to you? On the Web are numerous incidents, fortunately the version 3.5 the bug has been fixed, to the delight of many Android users and developers.