I can't quite tell, but how much glue did you use on your Anubias? It looks to me like you more-or-less covered the rhizome in glue, which is not good for the plant, and could have made it start to die- hence the rot, and the fuzz would then probably be a type of fungus. Personally I found using a bit of sewing thread to hold down my plants to be easier than glue, anyway.
In general I would say that fuzz on/near a wood element is normal, even if it's been soaked in water before it might not have started breaking down in the right way to fuzz over until it was in the aquarium. Some snails will eat it, but it'll also go away on its own and AFAIK
isn't anything to worry about health-wise.