This has always bothered me after the prequels. Obi-Wan clearly interacts with 3PO and R2 in the prequels… yet doesn't seem to recognize them in the OT? Maybe he was not trying to give things away to Luke but there's another line that doesn't work.
"I don't seem to remember owning a droid."
Uh you did. R4 remember?
"I don't seem to remember owning a droid."
Uh you did. R4 remember?