Looks like an area that has been repaired or replaced, but is it still the same slate tile?
The slight color difference is probably from being newly installed or repaired. But, would it look any different at night? In the rain? How about snow covered?
The truth is, those different colored panels are solar tiles for solar enegry. They are energized and could cover an entire roof. They also come in different colors.
These solar panels aren’t that new to building contruction, but they always stuck out like a sore thumb. Now, with new technology companies are able to make these panels “blend in” and look very much like the rest of the house and roof. | 
