Forum:KB:Obi-Wan, C3PO & R2D2

Looking for an explanation and unable to find it in the Wiki or Forums, but its a bit of a nitpickers errata question...

Why doesn't Obi-Wan Kenobi have any memory of ever having met C3PO or R2D2 in "A New Hope" when he worked with them throughout Episodes 1-3? After all, C3PO was built by Anakin! We also know from various resources that C3PO had his memory wiped repeatedly, but R2D2 did not and was considered a "Sentient" Droid. So why didn't R2D2 have any memory of Obi-Wan Kenobi?

Its one of those continuity anomalies that has some curious, but have yet seen explained.