The arrows are Dependencies. "InnerSketch" depends on "TopFillet", so that's one Dependency, or one arrow. The other arrows are Links to External Geometry (those magenta lines in "InnerSketch"). That's OK.
In the blue area, "InnerBottomSketch" depends on both "TopFillet" and "BottomFillet". So you can't edit "OuterSketch" without affecting both "PolarPattern" (the robot head) and "InnerBottomPocket" (the part that fits into the bottom of the head).
So for your model in "OuterSketch" you can't change, for example, the 43mm Horizontal Distance Constraint (Constraint13) to modify the robot head without affecting the part that fits into the bottom of the head too. If you change Constraint13 from 43mm to 42mm, it causes the male portion of the part that fits into the bottom of the robot head to become off-centered.
Scalpel78 wrote:What causes forking?
Usually someone toggles a previous Feature in the tree view to visible, and does some operation on it instead of always working from newest item in the tree. But I really don't know how you model got forked.
Edit: I see Norm figured it out.