Follow up explanation of how this "new feature" apparently works:

I match a group of cousins who descend from my 2nd gr grandparents George and Elizabeth through their daughter Barbara. Because this group of matching cousins all have another ancestor pair in common in their trees, the parents of Barbara's husband, ancestry predicts that Barbara's husband's parents are also my ancestors.

This same group of cousins and I also match a descendant of George's brother Joseph. Because this cousin group and I all share common ancestor Elizabeth (George's wife), ancestry predicts Elizabeth is an ancestor of the cousin who descends from George's brother Joseph.

I have DNA matches with three people who share as ancestors my 5th gr grandparents Lawrence and Barbara. These three matches also happen to share another common ancestor (3rd gr grandparent range) named Barton, so ancestry predicts that Barton is my ancestor. Barton is not my ancestor, he is related by multiple intermarriages of his descendants to descendants of Lawrence and Barbara several generations down the line. I am exploring whether I may be connected to Barton through his ancestors, but so far appears to be a wild goose chase.

Bottom line, most of the new "ancestors" are going to be in-laws, not ancestors. Folks new to family research who do not already have well developed family trees may benefit, but on the other hand it is more likely to further confuse them and result in even more impossible family trees. As always, ancestry is generating hints based on common names in family trees between matches, without any correlation to how people are matching. This is NOT science.