SUMMARY

I've noticed that the Aces Up solver can say "Unable to determine if this game is winnable" at the start of a game where the last four cards are of the four different suits.  In fact, the only way the game could be won without a single move on the last deal would be if the playing piles are empty (impossible) and the last four cards are the four aces.  The solver could look at the last four cards in the pile and check the suits at the start of the game.

STEPS TO REPRODUCE
1. Start Aces Up #1060233496
2. See that the solver says "Unable to determine if this game is winnable."
3. Deal all the cards and see that the last four are four different suits.

OBSERVED RESULT

Solver: "Unable to determine if this game is winnable."

EXPECTED RESULT

Solver: "This game cannot be won."