It may be the case that the instant something is experienced it can't be altered, however one monent after that, it can be. Due to our mind being severely limited in its ability to hold anything in short term memory for longer than a second or two, we suffer from a tendency to remember things incorrectly. Sometimes we might recall something we thought we saw a second ago which was actually not present, and rather is a result of some kind of unconscious priming of a previous occurrence. Other times, we might not even perceive the thing instantly and instead we have a form of destructive interferrence to that very memory, causing us to only experience the altered version.
So experience actually is constantly being altered every second, like a constant retelling of reality as we access memories and rewrite them as we access them. This is why eye witness testimony is taken with a grain of salt in the judicial system. We might think we saw a criminal with a red sweater but actually we are recalling an earlier memory of aunt Jenny in her red sweater. The mind is totally fallible.
For Dimebag, ...although I see that I have yet to learn how to copy the quotes, "it's only my second day"
This may have been mentioned somewhere in the pages of this discussion that I haven't read through, I just wanted to point out this phenomena you speak of is known as the Mandela Effect. It is an alteration of a memory through recalling that memory and is sometimes a 'false memory' because it is not entirely factual. But it can seem that way to the person recalling it, because for them it may be entirely true until proven false.