In the latest snapshot update, dying wool/glass gives you an opposite color of what the dye is. For example putting light blue dye surrounded by glass gives you brown glass. But when you surround coco beans with glass you get light blue glass. And if you shear a white sheep you get black wool. This happens with all the colors.
Duplicate – If you have not, please use the search function in the future, to see if your bug has already been submitted.