Why are you keeping a 99% humidity level?
Unless you are keeping dart frogs or something, there is no need for that level of humidity constantly in the tank.
In the first part of the 1990s I used glass aquaria (29 gallon) to successfully breed and keep several species of very healthy chameleons.
My strategy in this limited ventilation system was the following-
Paper substrate (absorbs moisture after light misting, then gives off humidity as it dries out over the next couple hours).
A small live potted plant (pothos vines I used) in a 4-6" pot. These also gave off a little humidity from the soil in the pot and the leaves respiration.
The biggest rule was never ever provide a constantly damp and humid environment. I always made sure the tanks and paper were completely dry between mistings. Usually mistings were 2x per day. For babies more often and no paper substrate, but mistings were just enough to get a haze of water droplets on the glass, but no puddles in the bottom. For babies 3-4x per day was enough. All water was evaporated within 1-2 hours. Constant dampness caused babies to deteriorate quickly in health and was avoided at all costs. Misting was mainly for a little humidity. Drinking water was provided with drip systems and catch bowls that were cleaned daily.
I'm spelling things out so specifically because the system worked and maybe might give you some ideas to compare with. I never had mold in my tanks. It worked for veileds which I kept around 100 under the basking spot in those days (was the recommended temp then), panthers, carpets, dilepis, as well as cooler loving chams like montiums, campani and quads. Constant humidity isn't necessary to prevent lizard jerky.
Without ventilation, don't use substrate that is constantly damp if that is what you are doing. (Just a guess?). And 99% humidity constantly is probably too high for any chameleon in a limited ventilation situation...
