I've never heard of that! I've raced with it and one of the things they check is the brake fluid to see if it's clean and full. In P.R. the rules are not as strict as SCCA or NASA but I've also done driving schools with the PCA and if you don't have a Porsche and if they're short instructors they try to find a reason to keep you from running. I had ATE Blue and I passed.
Now I'm curious myself now, but I think it must have been a local thing.

Les