Why is my chameleon doing this???

Please help, my chameleon (winston) is acting weird… Every time I put a cricket in his cage, he goes for it. By going at it with his tongue, but half way when he goes for it, he stops, and pulls his tongue back inside, he does this several times, until he finally goes all the way and nabs the cricket, so wats wrong, we recently changed his lighting, and we never really give him supplements of any sort. Sooo what could be the issue?? I need your help fast!!