[Masterjun]

It seems I got an ambiguous sudoku puzzle. https://i.imgur.com/AUiLP7J.png

I read somewhere that sudoku puzzles should always only have one solution or they don't count as "real" sudoku puzzles.

[notnaut]

I had one with at least two solutions as well and one of them was classified as invalid, though it should have worked.

[alabhyajindal]

That's unfortunate. I am looking into this.

[alabhyajindal]

Thanks for pointing this out, I didn't know about this. I will look into improving the puzzle generation function.