Why not test it on the mobile if you are releasing it for mobile? That seems like a blunder. Check it out yourself on mobile to see the issue I guess ?
It's also test on mobile.
Everything works.
A player report me another level with the same issue, he continues making some other levels came back to the one with the bug. And this time the solution works.
Same phone, same level, sometimes it works sometimes not.
I would think the problem might be the position because i check the color of the squares in the lines and column with the position of each square and column.
But it's hard to check on other people phones