I noticed when my male veiled chameleon is getting sprayed with water emerald colored patterns appear from a lighter green. I didn't know if anyone has come across this also.
This will happen a lot, but mainly when you first get your cham (from my experience at least). This means they are stressed, or sometimes when the are trying to absorb heat. They aren't going to turn brown usually, but its just a warning sign that they want to be left alone. Never stop misting though, because usually they will start to not mind it as much.