In the original movie Obi Wan Kenobi doesn't recognise R2D2because he has never met the droud. When Lucas came to write the prequels he decided that he wanted R2D2 and C3PO in the movies and the only way he could have them in properly was to have then intwined in Obi Wan and Anakins part of the story.
Obi-Wan Was Pretending He Didn't Know R2-D2
Shortly after claiming to have never owned a droid, Obi-Wan tells Star Wars' most hotly debated lie by claiming Darth Vader "betrayed and murdered" Luke's father, Anakin.
Because Vader's past life had been obscured by trauma, it's possible that the memories of the droids weren't present at the time. Additionally, most droids are designed to be identical to another of the same model. Vader could have mistaken the two as any other generic droid, not realizing their significance.
Meanwhile, R2-D2's cameo in Obi-Wan Kenobi comes a bit later on at the 38:45 mark of the episode. He's briefly shown on the right side of the screen as Bail and Breha Organa talk about Leia. The appearances of R2-D2 and C-3PO in Obi-Wan Kenobi work perfectly within the established Star Wars canon.
“Carefully moving through the swamp while staying beneath the fog, Yoda soon spotted the boy and his droid unpacking their supplies. Even though the droid was caked with algae, dirt, and stomach fluid, its appearance and familiar blips were still quite recognizable. R2-D2.
He didn't recognize him because again, they all look the same & it was decades until he saw him again. There was no reason to believe he or R2 even existed anymore. Do R2D2 and C3PO know that Darth Vader is Anakin? Threepio had his memory wiped at the end of Revenge of the Sith.
The short answer is that creator George Lucas had no idea Leia would end up becoming Darth Vader's daughter. But Star Wars books and comics have tried to address the decades-old plot hole.
However, because he saw their dynamic as a source of weakness, he opted to spare them. Now that the Empire had gained the upper hand against the rebels, their survival didn't mean much to him in the grand scope of the galactic conflict at hand.
However, R2-D2's memory is not wiped; as a result, R2-D2 is the only surviving character at the end of the saga who knows the entire story of the Skywalker family. Both R2-D2 and C-3PO end up in the possession of Captain Raymus Antilles (Rohan Nichol) onboard the Tantive IV.
Padme gives her droid R2-D2 as a gift, and new co-pilot for Anakin.
R2-D2 was built in 33 BBY on Naboo and belonged to Padmé Amidala. The following year, he became the property of Anakin Skywalker, who he had a trustful friendship with. R2 served in several missions during the Clone Wars, alongside his owner.
When we first see R2D2 (in The Phantom Menace), he is one of several robots aboard Queen Amidala's space cruiser fleeing Naboo for Tatooine. He clearly belongs to Padme.
After Cad Bane had kidnapped and ransacked the memory of C-3PO and R2-D2 for information on the Senate Building's layout, he only had the incident wiped from their memories to avoid having any suspicion falling on him.
Although Lucas portrayed R2-D2 as a defiant droid who refused to listen to his master's orders, the theory video claims R2-D2 wouldn't stay with the ship because the last time he did that, Anakin never came back.
She also knows Obi-Wan, and she knows him well. Her holographic plea for help, already iconic, will never be the same. She knows Obi-Wan's real name as well as his alias of “Ben.” When Luke comes barging into her cell and says, “I'm here with Ben Kenobi,” Leia jumps off the bunk in an instant.
Leia's ordeal. In the rough draft of Star Wars: Episode IV A New Hope, Darth Vader tortures Princess Leia with powerful electroshocks. In the incarnation of the second draft of A New Hope, Leia is replaced by Deak Starkiller, the brother of Luke Starkiller (who would become Luke Skywalker in later drafts).
As the theory explains, Wookiee culture dictates that when Wookiees lose a loved one, they are not supposed to touch anyone until they have had time to grieve in private. This explains Chewbacca's actions.
As Slash Film reports, whenever Luke Skywalker speaks in The Mandalorian and The Book of Boba Fett, it's not Hamill's real voice that the audience is hearing. Instead, the output of a highly advanced voice synthesizer called Respeecher is responsible for Skywalker's voice.
During the Imperial Era, a human female nurse served the Galactic Empire on board the Death Star under the supervision of a doctor. They both served the Sith Lord Darth Vader as his personal medical caretakers. The nurse became obsessed and psychotically in love with the Dark Lord of the Sith.
Before she became a Jedi hunter, she had possession of a droid. However, it was taken away from her, like many of her past belongings and acquaintances. During her time as an Inquisitor, the Third Sister wore black armor with a cape, and wielded a red-bladed Inquisitor lightsaber.
Beginning his service in the employ of Queen Amidala of Naboo, R2-D2 wound up serving Jedi Knight Anakin Skywalker during the waning years of the Galactic Republic, often accompanied by the protocol droid C-3PO in many adventures throughout the Clone Wars.
This means Threepio would now remember the identity of Darth Vader, the events of the Star Wars prequels, and Luke and Leia being siblings. All decades too late, of course.