Ok thanks for the info Michael.
Ya I looked everywhere and did searches but couldnt find a default setting to turn this off. I always do a border/ picture frame, but do the blocking for it different (than Chief's auto build). Good for those who like it that way, but for me I'll have to delete them. Will have to do at end before i send to print/ layout, as i deleted those framing blocks when they first came up as I built the deck, but then as I made edits to deck footprint with auto rebuild frame on they came back. Little nuisance but I'll make it work.