Near the end of Harry Potter and the Goblet of Fire, Dumbledore realizes that he has to take action in reaction to Voldemort's return since Fudge won't. In the hospital wing, at Harry's bed Dumbledore gives out instructions to his adult allies. After Sirius and Snape shake hands then Dumbledore gives instructions to Sirius:
Sirius, I need you to set off at once. You are to alert Remus Lupin, Arabella Figg, Mundungus Fletcher—the old crowd.
This happens right next to Harry and in fact Harry starts to object to Sirius leaving. So Harry has to have heard Dumbledore say "Arabella Figg". But in Harry Potter and the Order of the Phoenix, Harry is shocked at learning Mrs. Figg is a squib and knows Dumbeldore:
"You're—you're a witch?"
"You know Dumbledore?" said Harry, staring at her.
Is there anything out there (Pottermore, interviews, etc.) to indicate why Harry didn't realize who "Arabella Figg" is Mrs. Figg, his neighbor? Or was Harry just not paying attention to the details when he was laying in bed after the ordeal of the cemetary and the trauma of Voldemort's return?