The style does not get applied correctly. If you saw the attached animation, the raster data's color scheme was changed from 9 classes to 2 classes. However, after apply the new style, it does not get correctly applied. You still can see way more than 2 color variations. In fact, it holds the original number of class of 9 that is recorded in initial sld file. Also, if you see the right bottom corner, you should be able to see the opacity is also different. The right bottom color is almost transparent.