It wasn't so common that I can tell you definitively. There are only a couple examples I've seen. [ A tiny blip of something, not quite guilt. ] But generally... a loose soul is naturally drawn to a suitable vessel. It must, or the soul will disperse.

If a vessel is perfect enough, the soul can even be drawn into it against its will. And because the soul contains the "genetic blueprint" of an individual, it can reform its new vessel into its original image. Once that happens, you might never be able to tell that the soul has taken over a new body... unless you can tell somehow that the "mind" is missing.