It's not unusual to change your mind about retirement, it's very common in sports.
It's also well documented that he told Pep 'when you leave Barca, do not sign anywhere else. Call me' and then Pep chose Bayern. I'm sure there were many names in contention for the role and not just Moyes. People make out like the board went to SAF and said 'who do you want to replace you' SAF said Moyes and then they replied 'okay cool, hired'. In reality, it will have been a very length process involving the entire board and considering a number of factors, that SAF's opinion would only have been a part of.
I don't know about you but I've either recalled something incorrectly in my life, or even flat out lied to someone before. I'm sure you will have at some point in your life and yet that doesn't mean that even 5% of what I say isn't true and I'd wager the same about you too so I find it to be a non-sequitur to act like because there are examples of him saying something that wasn't quite true before that any significant portion of what he says is therefore false or that there's doubt cast over it.