Since you are comparing two classified images with a small range of values, instead of using the image analysis window functions (especially given the cryptic result), why not just use spatial analyst functions?
There are a number of ways to do this, but I suggest using Combine: This will output a new grid with a single value for every unique combination of input values, e.g. forest-forest, pasture-forest, forest-pasture, pasture-pasture, etc. The output attribute table will show all original and new values, allowing you to assign new names to the mapping (e.g. deforestation, regrowth, no change, etc.).