AI bug in [N]

[uttumuttu]

In the expert mode, there's apparently an AI system that determines which squares are deducible and which are not.

Take a look at this image[imgur.com]. The square marked "!" is a black square. My deductions tell that it must be a mine. However, the game won't let me mark it as a mine or a non-mine.

[MikoKisai]

Expert mode checks your deductions and only allows them if they are provably true. If it cannot be deduced, it won't let you mark it either way, regardless of what the final solution might be.

If I'm reading your notes correctly, you're basing your deduction off of R3C1-2 adding to 0, i.e. if one is a mine, so is the other? That's not correct: the 2 in R2C1 must have precisely 2 mines around it, and it's either both of the black cells or both of the gray cells. This means precisely 1 of R3C1-2 is a mine, and that likely breaks your deduction.

[uttumuttu]

You are correct, my assumption of R3C1-2 adding to 0 was a complete miscalculation.