Forced Termination

Forced Termination (強制終了) is unique amongst the other phenomenons in the sense that it is not initiated by the Heartseeds, but automatically activates under certain conditions. This phenomenon appears during the Nise Random and  Asu Random I arcs.

Description
Forced Termination automatically activates in response to two or more people experiencing a paradox as a result of a phenomenon, for example, if two or more people observe the same Illusion Projection at the same time. Another trigger for this phenomenon is if there is a risk in deteriorating mental state or injury, especially when theres physical violence acted among the members. The ensuing paradox will cause the observers to have their memories reset to before ever encountering Heartseed. Heartseed apparently has some control over this phenomenon and was able to return the memories of Taichi and Yui, but not Oosawa. In the case of Taichi, he has a desire to go to the StuCS clubroom but does not know the reason. This shows that the memories are not completely erased and parts of it still remains. When this phenomenon happened in the "Isolation Dimension", the members involved would disappear from the world which many mistook as returning home.