I have a really interesting game going with Cofail (Him Houdini, White, Me Stockfish, Black) where I wanted to test the Steinitz Variation of the Scotch against a strong engine.

http://www.chess.com/echess/game.html?id=44757202

White never lost the advantage, even got up to about 1.7 or so at a point.

But, now in an unbalanced material ending, Black has built a little fortress, and White's task seems difficult.

Interestingly, for the past few moves, Stockfish evaluates the position between 1.1 and 1.2. But that's not all, it gives exactly the same score  for about the top 5-8 alternatives, almost any non-losing move scores that. For example, for Black's 62nd move, I have 6 moves evaluated at exactly 1.09.

Is this a sign that Stockfish thinks White cannot make progress, and the game is headed for a draw?

I know it's a game in progress, but seeing it's an unrated engine game. I don't think the normal rules apply.

Houdini is the same for me, it is a mystery.

but then Rxc2+ and how to make progress.