Welcome to the absolute worst aspect of chameleon keeping - bulk crickets means lots of dead stuff in the cricket container. That attracts our sworn enemy, the phroid fly.
These little wretches are so vile, I can't fully describe how much I truly depise their entire evolutionary history.
They thrive on warmth and moisture and death. Dead crickets, dead dubia, dead eggs - heck, maybe even good eggs, all attract these things.
They are the reason you shouldn't put holes in your egg containers - nothing like finding an near-term egg pulsating with hundreds of maggots.
They are easy to control, if your setup is done properly.
Dry those SOB's out - keep your cricket bin well ventilated - do not try to shut them out - these flies will get in. The key is to make the conditions unsuitable to their larvae (technical term for: absolutely disgusting maggot that is merely a step above parasitic worms on the level of vileness).
What works for me 100% of the time: A 100 Watt bulb suspended above my cricket bin 24/7. Keeps them warm in the winter, dries all the dead crickets. If you spill water, or some cricket bin detritus gets moist -they will move in - the heat lamp prevents this from happening. Make sure that the majority of the bottom of the bin is heated by the light - might take some trial and error.
I switched to a 26 Watt CFL bulb this summer - cause it was getting warm. One weekend the phorids came in (open door). I noticed the dead crickets were moist on the bottom of the cage, and dumped th ewhole lot out in the yard - about 1000 pupae were stuck to the bottom, under the dead crickets. would have been BAD.
BAck to a 100W bulb, no more maggots in the crickets... I need to put screens on my roaches, though...