I have seen urates like this over the years where the tip of it is white and then mostly orange. My chameleons are well hydrated and still it happens. I honestly, do not worry about it all that much. I have also noticed when they don't poop for days at a time, the urate will not be as white. Everyone always assumes that if the urate is orange then they are dehydrated. I am not so sure if this is 100% true. Just my opinion. I may be wrong!