Could there be an explanation in string theory for the occurrence of residual hauntings?

There's nothing stopping someone from speculating, but you're referring to a scientific theory (more of a hypothesis, really). The scope of string theory is limited to the physics of the natural universe, and the language of science is math. A linkage between scientific theory and paranormal hypothesis like the one you suggest would not exist, by definition, so any such explanation would be orphaned. 

We do NOT know when they are supposed to happen NG. Where the hell did you get that from? We aren't talking rainbows here. If we knew, there would be the same turnout as for an Eclipse. Lines of people with cameras. Tim, there is a good chance that we are seeing people who are alive and well with true intelligent hauntings, but residual maybe some kind of natural recording by nature. We invented vision before sound so maybe nature is the same. In theory, nature can record sound. A bird sits on a bush and sings. The vibration travels into the branch to the tip. If the breeze blows the bush, the end of the branch may drag through damp clay. Once dry, maybe in a thousand years, you could drag a stylus through that groove and hear the bird song. Granted, there will be no hi-fi there but there you go. Maybe nature can somehow do the same with vision, showing a replay of some event. The events that have been seen to repeat are often mundane things, an old woman picking flowers maybe. They are not always reenactments of famous battles or executions. Maybe some sort of mirror effect that reflects time. I can only give buts and maybe's but it sure shows that we don't know everything.

First, let's be sure residual hauntings are a real phenomenon, and there are some legitimate doubts on that. Why do residual hauntings only appear for folks with no cameras or video? Okay, assume they're unpredictable, but we do know where they are supposed to happen. That there are no recordings is troubling or should be to someone wondering what they are and how to explain them.

Outside of a predicted energy uncertainty down around the Planck scale it's difficult to speculate about anything as small as a string would be. And if string theory is correct those strings are very very small.

You specifically mentioned residual hauntings. Which brings me to a SWAG moment. String theory indicates that there are unknown spacial dimensions. Could unknown dimensions of time also exist? If so that could explain residual hauntings (also dark matter, but that's another topic).

There's much more we don't know compared to what we do know. Often all you can do ponder and guess. 

i dont think so