I guess the idea is that the initiation ceremony involves amnesia about the tadpole insertion. The player knows what it is that grants the psionic abilities. A potential threat. But the absolute sends dreams nonetheless. It promises you power and support but it also wants you dead. It appears to be mad. Maybe just sloppy writing.
You were most likely on your way to Moonrise and a memory wipe in service of the Absolute, the Illithids were bringing you there. The problem with this theory however is that Shadowheart already has memory loss and is probably a brainwashed cleric of Selune, on top of that she has a Gith weapon that we know nothing about. Something does not add up there and I don't know what was written first.
