Robin Fernqvist

Nvm, i realized that you also need to increase the resolution of the "base.png" inside assets\minecraft\textures\entity\shield
for it to display properly ingame. Sorry bout that.

Well yes, that's how they work currently, and if they're not intended to work this way, it's a bug.
If you don't know for sure that this is how it's meant to be, your comment just doesn't make any sense.