They made it fairly ambiguous as to whether they were retconning stuff or just having Deathstroke playing mindgames with Geo-Force and Beast Boy being in denial. But yeah it was a pain to see even kinda said.
I still have no idea what the story is with Deathstroke poisoning Geo-Force by giving him his sister's powers. (Powers do not corrupt people in and of themselves, I'm looking at you writers who made Black Adam's powers inherently evil and bad for Mary.)