In this case, I have noticed that your gif is located in disposal = 3 which states that it requires the previous image because it renders incrementally. The error and issue I am facing is that the gif is completely black and not white.
Here are the possiblilities:
if (disposal==0) s="no animation";
else if (disposal==1) s="leave image as is";
else if (disposal==2) s="clear with background";
else if (disposal==3) s="restore previous image";
While rendering this with my decoder, it looks like the following shown below:
Which ensures that there are two possibilities at this situation as such. One could be a transparent image with a background but still, even an average image viewer would display the same and hence, this might not be the case overall. These days, the browsers of the WEB rely on undocumented custom made extensions added to GIFs extension packets which ignores the GIF File Format for various aspects of rendering. All these use the same image LIB for decoding the GIFs with the presence of bad design/code. I presume that your GIF has an extension packet which commands the browser to use different disposal methods than the one which is present in the GIF header. This makes the GIF a buggy GIF and only a decoder of a buggy GIF can render it. The white lines have gaps between them and are not an aliasing bit. Also an incremental render will not work with a non black colour background and hence, the decoder must ignore the GIF background colour.