I am using Windows 10, and the font size is 100%, which is the default of Windows 10. I'm using a desktop.
But I have also seen this error on other computers with 4K monitors attached. The computer is running Windows 7.
That computer is my personal work computer and is currently not accessible. I am currently home. Sorry.
I live in another non-English speaking country, but I am a programmer. I have witnessed js error on v135 you made. I mainly use c# and c++, but not javascript, so it may not help. Still, I want to help you as much as I can.
In my opinion, in the process of converting an image to a floating point between 0 and 1, I want to check if there is any error in the position of the pixels. Floating point errors sometimes make a roundoff operation. The key to this problem is that the dithering doesn't work in areas where it should be. Somewhere, it seems that the pixel is clearly not recognizing where it should be taken.
Or, it may be that the dithering position is pushed by one and the calculation is not possible.
I love this program so much that I want to help improve it whenever possible.