
I don't think he's misremembering and instead it's probably just a different perspective; since little A was a kid, the uncle probably looked/felt bigger to him and also adults often behave differently towards children than towards adults so it's entirely possible for the uncle to have put an "strong reliable uncle" act in front of little A when he was a kid. It's also possible that the stress of this entire messy situation with the hybrids made him more anxious/less confident.
Since the last time little A saw his uncle was years before any of the "farm animals" saw Mr A for the first time it's also entirely possible for little A to only know him with a beard and the hybrids to only know him without.
it's just a little strange how the way little A sees uncle is a buff bearded man who's so happy-go-lucky, but when K explains him, uncle looks fragile though he has muscles and no beard at all. and he seems different from the guy at the bus? Idk? maybe he's uncle, maybe he's not.