10.08.00.51 Update 8
By default in OpenPlant PID, Color for Flow Arrow is set as white. Even after modification in Piping.cel it does not get reflected in OpenPlant PID. This wiki will help in modification of arrow color and updating the existing arrow color..
If above problem still persists, then please create a Service Request and contact the Bentley Product Advantage group. Please include a list of all relevant details to get in depth analysis for a solution or workaround