Thank you for posting your idea. I suspect you have a specific example of this event as STAAD.Pro is designed such that if a member is split in the GUI using for example the Insert Node tool, then both the original member and the new one should be assigned the same material that was assigned to the origianl. If you have an example of that not occurring, please log this as a service case using the Bentley support portal and the team will work with you to identify the cause.