Soak them in 3% hydrogen peroxide at a 2:1 water/peroxide for about an hour. Then apply Recharge after the reset.

The humidity is obviously too high. Lowering the humidity will kill the mold. Hot and humid is what it wants.

It’s a big problem out west where clones are shared and sold at scale. It’s all anyone talked about for years. This is why we tell new growers to source their own genetics from reputable seed breeders. Buying other peoples problems is a known thing.

As a grower, you have to be prepared to kill shit.

I don’t like restricting seedling roots. I’d transplant it soon. Roots are supposed to grow out of the starter media. Clones are different and need a humidity dome unlike seedlings. After you see the few initial roots popping out, you have a few days to acclimate clones out of a humidity dome while the roots continue to develop enough to transplant.