[quote="crystally"] It's dark and it's at the lower part of the ears. It's in the right place. No mistake here at all.[/quote]
[quote="TheDoctor"]for shadows to appear like that on the ear the light would have to come from another angle than above.
To be properly placed on a TLK lion, they would be at the top of the ear.

Like so.[/quote]
But nevermind then

I've noticed a couple more shots where the shadows on adult Simba's ears are wrong, but they're never as dark as they are in the scene mentioned in this topic, thusly why I thought they could be markings. They could be ear marks
with shading

In some shots we can't see the edges of Simba's ears at all, so they're generally pretty inconsistent.
In conclusion, I will consider it a colour or shading fault. Whether it's both or just one we will never know.