I bring this up again because I made a "misplay" at nationals at the end of one turn and I didn't catch it until catch it until the middle of my next rescue. The scenario was I rescued with Moses and my opponent played Burial on the LS. For whatever reason, I proceeded to discard my Moses. Next RA I used AutO and looked through my deck and couldn't find Moses and then realized I had discarded him. My opponent said I couldn't put Moses back in my territory and the judge agreed.
I think there is a lot of grey area here, and so either both players should agree on what is to be done, or else you just have to go with the judge's decision.
In general, I think it is good to fix mistakes in games. However, the more time that passes after the mistake, the more I would lean toward just leaving it and moving on.
The most important thing to me is whether the mistake has already affected any other game actions. So in your case, I wouldn't have a problem with you putting Moses back in your territory normally. However imagine if you had Chariot of Fire turned on, and your opponent had played his Destruction of Nehustan to get rid of that artifact because he didn't want you to get Moses back. In that case I would NOT let you take Moses back out of the discard pile because his presence there had already affected other things.
