Audio problem: As Ash backs up from the bridge, he squeals his tires on the dirt. (00:09:55)
Audio problem: When Ash is standing by the self-playing piano, it is clear that the keys being pushed are way out of sync with the music. (00:14:25)
Audio problem: When Ash is struggling with Linda's head, he bangs it against several objects. At one point he slams the wall, which sounds like a large metal panel or piece of aluminum siding. The cabin is made of wood. (00:19:45)
Audio problem: It's quite obvious that all of the grunts and sounds of terror that Ash makes while his hand is attacking him in the kitchen are dubbed. (00:28:45)
Audio problem: After Linda's head is possessed and bites Ash's hand, as he's getting up and going to the work shed, his mouth doesn't move as he says the word "work-shed", and it is obvious that it is dubbed in. (00:28:55)
Answer: Sam Rami could not get the footage of Evil Dead to use in the sequel, so he remade the movie in a shortened form for the beginning. Since Linda was the only original character other than Ash to come back he included her in the recap but deleted the others as not to waste time. An in universe answer could be that trauma of losing his friends made Ash block them out and rewrite history in his head, except for Linda who comes back to haunt him in the movie so he is forced to deal with it.