Random files inside torrent get deleted

[Nameless]

I am downloading a torrent with several files, and have been downloading them one by one, in consecutive order. The other day, I think it was after deluge crashed, Some of the files I had already downloaded, were reported missing by deluge. I re-checked the torrent, but they were gone. I downloaded them again. Today, there was no crash, but I just opened deluge, and two of the torrent's files are missing again (not the same ones). I re-checked and also tried to use one of them, but they are gone, as if they were deleted. I am just reporting this as a bug, I don't think I can solve it.