Ice and Fire adds a new aspect called "Draco" to Thaumcraft, but Thaumic Additions also adds "Draco" which causes a conflict.
The conflict causes the Draco aspect to have a fake version which is extremely unstable. Trying to extract this fake "Draco" as essentia crystals or trying to obtain a phial of it will fail to form the desired item. Directly moving this essentia to a jar and breaking it will sometimes crash the game. The game cannot handle a container that is filled with this fake aspect.

This is the part of IaC that handles the thaumcraft compat.

static Aspect getOrCreateAspect(String tag, int color, Aspect[] components, ResourceLocation image, int blend) {
Aspect a = Aspect.getAspect(tag);
if (a != null) return a;
return new Aspect(tag, color, components, image, blend);

There is a NEI addon that allows the player to see all aspects that exist in the game. Thaumic Additions "Draco" is taking precedence over the IaC version. (note the search term "draco" only finds one aspect)

As for the item aspects, Ender dragon egg contains 100 real "Draco" while IaC items have this fake "Draco". It seems that the fake "Draco" has the wrong color and ResourceLocation.
I suspect that the bolded area only fetches the name and completely forgets about the rest. That is why the fake "Draco" has the IaC-designated colors and image.

Since I am relatively new to Java development, I do not have the knowledge to properly fix this. I have no idea how to properly decompile and re-compile a mod. I am sorry I could not help further.