I think olivia got it right how to limit the mold growth
Mold is spread thru the air, by water, or by insects and can land anywhere and grow. The environment is just too good for them to pass up in a wet plant if you have spores flying around the home. They live on any dead material as they are recyclers. Left alone it will cause problems with your orchids. So my thoughts are mold can hurt your orchids if left unchecked and untreated.