I was strolling along the river bank when all of a sudden a bloody red wash covered the ground. It was forest and the terrain was this lovely scarlet shade while the water turned magenta. It stayed this way for several seconds, probably around a minute. After a minute it flowed away starting from one side of the screen. It may very well have had something to do with the fact that I was wandering around with a dowsing rod in my hand. The colour was the same, I think, as that odd red pie wedge shaped indicator that sometimes flashes.
Not a serious bug by any stretch of the imagination, but still momentarily disconcerting.