Okay and with Scott's post I'll post what the HJ ruled.
The HJ opted to rewind the game state to the last legal time. He did this by adding the card in Andrew's hand to the pile of 7, then he randomly selected one to return to his hand (this was done because it was impossible to tell if that was the card he started the turn with. all he knew is that it was one of the 8 cards), he then put the seven cards on top of the library and shuffle it to return it to a randomized state, finally he had Andrew untap his lands and return dig through time to his hand. Andrew then cracked the fetch-land and recast dig through time. If you'd like to discuss this further I request you please do so in a manner that does not attack the judge's ruling, however questions are fine.

I'll quote part of IPG 1.4:
“Backups involving random/unknown elements should be approached with
extreme caution, especially if they cause or threaten to cause a situation
in which a player will end up with different cards than they would once
they have correctly drawn those cards. For example, returning cards to the
library when a player has the ability to shuffle their library is not
something that should be done except in extreme situations.”

This pretty much means that we shouldn't back up if we need to return an
unknown card from hand to library if there is a fetchland in play.

Originally posted by walker metyko:

I request you please do so in a manner that does not attack the judge

and I'll add that I hope everyone will always, in any thread, do as Walker suggests here.

It sounds like your HJ performed a back up by the book; while I agree with Shawn, that I probably wouldn't back up in that same situation, it's good that this back up was consistent with our guidelines.

d:^D

Originally posted by walker metyko:

He then put the seven cards on top of the library and shuffle it to return it to a randomized state

I don't think that we are supposed to shuffle the library. It does seem better in this situation (otherwise Andrew can choose to dig through either the seven original cards or seven random ones), but that is not supported by the backup procedures.

Florian, that would be from the SEVEN extra cards looked at…

Ah, yes, there is that. That sounds like an excellent reason.

I'd probably leave things as are, with warnings as appropriate. I'm not going to try to rewind that mess.