Comment 79 for bug 453579

@mabovo: a regular fat32 filesystem only supports files up to about 4GB, wich explains your problem.

I haven't expirienced this on ext4 yet, but I did notice some corruption on ext3 a while back, nothing important, but it could have been corruptions introduced with the transfer of the file. I don't know how you downloaded it, but it might be a clue (http, ftp, bittorrent,..?), not every protocol has the same level of corruption checking.
Although I'm afraid it is in the filesystem, in my case with ext3 it was a torrent, first hash checking passed, a month later it didn't.