So when I ran across them _again_ in another part of my tree, I was very, very cautious about filling in fields. I knew how annoying it was to get that wrong, because ancestry.com does not support merging individuals.
Anyway. I entered it all very nicely, and no, I could not possibly tell you the implications, because I can't demonstrate that it's anything simple like a first cousin marriage (for one thing, I haven't been able to dig back to grandparents on all the relevant people) -- it might be, but I can't prove it -- but worse, whatever that was, their offspring married someone else in my tree.
It does not display well. Seriously. Does not display well at all.