Weird sepia contrast explosion

[NeXEkho]

I'd like to start out by saying first of all that I'm not a serious photographer. I don't have any decent equipment and I mostly photograph for texture work and research rather than as art. (I'm a 3D modeller)

With the default auto settings on my Finepix S1500 (a basic superzoom point-and-shoot) I've taken close to 8000 photographs. And three of them, despite being taken on a glorious blue summer day in all instances, said days being months apart, look like this: (I've lost one, sorry)

In the second image, fstop is 1/5, exposure is 1/800, ISO is 64, focal length is 6mm and the exposure bias is 0. Flash was disabled in both instances.

Photos taken 10 seconds before/after are completely normal. It's odd; there's a fog added, the whole scene is sepia and the contrast has been turned way up. Is this a well-known phenomenon, a possible rare software bug causing it to choose wacky settings or something else? Because I love how it's come out. If I could trigger this condition, that'd be awesome. Thanks.