In the PT Obi-Wan and R2 fight together during many battles but when he sees R2 again in ANH, he clearly has never seen him before when he says “I don’t recall ever owning a droid”. So after 17-20 years he doesn’t recognize his own copilot? What are we supposed to think? That Obi-wan went senile?
I thought it was another “certain point of view” thing, since Anakin says in Attack of the Clones that possession is forbidden for a Jedi, so the reason Obi-Wan doesn’t remember owning a droid is because he never technically owned anything.