Antoine. We have a pit road issue with this track too. We all got black flags when speeding over 40 mph. They were clearable if entry and exit are below 40 mph. There is a catch... If you speed going in and do a driver change, it clears the BF instantly unless you speed again on exit.
Also remember to stay to the right guys. It will be a stop n go if you go left too soon.
Thanks.