Hi @JayZay, thanks for taking the time to try and replicate the issue. 
I think I’ve figured out what is happening.
When adding brim ears, a little warning appears if your brim type is not set to Painted. Clicking the Set the brim type to “painted” text changes the brim type of the Object to Painted. I expected it to change the Global setting. It was only after looking in the objects tab that I realised what was happening. This makes sense now why the global setting was being ignored and I was not seeing any brim.
I wonder if clicking that text should offer you a prompt to choose to set the brim type to painted globally or for the object that the brim ears are being added to.
So I guess this was just user error 
I’ve marked this as the solution.