I have the same problem. This only started with 3.0 and continues with the latest build update. In my case, when I download file A within a torrent and it finishes and downloads file B, file A will later say that the data is invalid and I have to redownload a certain chunk. File A will finish and go on to download file B or C and file A will give the same error and redownload the same chunk over again. This has happened with two torrents so far. Both of them being mp3 albums.