What you have described is interrupted marks. Just my humble opinion this is a very poor setup! Some will say it test memory but more than likely it will result in handling series and wipe out the marks. It is a way for judges to fail dogs because they themselves are challenged as to where they should place the birds or the cover is very very poor so this is what they decide to do to challenge the dogs. The F/T advisory committee has been discussing this for a couple of years. I not sure of the out come but I have not seen this in years.