When using reiki for manifestation it takes on the quality of your dominant thought. This is a characteristic of manifestation itself and not specific to reiki. The thought or feeling could be conscious or subconscious – if there is something still lurking below the surface from childhood that will be the dominant thought until it is shifted / healed so the manifestation shows you that something still needs work. It is making the process obvious so that we deal with any residual issues.
I hope that is clear enough – based on my experience. The healing process is both internal and external (philosophical,psychological,biological,social and economic).