Are you using Electrolyte Suppliments?
I suggest using them, and then cutting the light period down to 14 hours a day, and then 10 in COMPLETE darkness with no disurbances. The electrolyte suppliment will have visual improvements for your chameleon, and it will help them more effeciently absorb the UV.
Chameleons who do not have the right lighting schedual will develope serious negative long term effects.
Also, Chameleons can get sunburns and skin irretaions from too much UV in long periods of time. Just as humans do. Where I live, in the summer, you get your daily maximum or Vitamind D and UV in only 4-8 minutes in plain sun. After that sunburning start to take effect and UV overdosing, leading to symptoms of heatstroke.
-----
1.1 Bearded Dragons
1.2 Maroantsetra Panther Chameleons
1.0 Long Tailed Grass Lizard
500 Escaped Crickets