It didn't seem to happen after i did anything specific. What I sort of remember is hearing him start to chase me at one point when i was sure he wasn't in the room with me, and the heartbeat noise started. I'm assuming his detection got messed up some how, and he saw me from a different floor. when that happened maybe his pathing got messed up because he was sort of stuck between a couple things. Not sure, and I'm not a programmer, but that's the most I remember!