It is about sensation and perception. What we see is not passed in pixel by pixel but by pattern: line, dot, square... then reconstructed in the brain. This is heavily influenced by things like emotion, expectation and past experiences....
Recall of the memory is reconstructed but not the same was as described above. It reconstructs the scenario by putting together things stored in multiple areas of the brain.
Nothing is clear about the whole thing I just talked about, not clear in science yet, and I only know a fraction of what scientists already knew.
Essentially I am making only one point here: Both are reconstructed but differently.
Hearing is too, I am experiencing it these days, what I hear is not what people say, sometimes, not because I did not hear it, but because, I guess, some sensors in my ear are deteriorating, missed some key "sounds", then when the brain tries to percept it(interprets it), it came to the wrong conclusion.