After looking at the command line graph it's more clear that there was a branch created off of master and then another branch created off of that branch. Because there were no commits while those branches were being created they essentially share a common point which is represented in ADOS as that perpendicular line in addition to the other two lines.

If anyone is having trouble seeing how they relate, imagine that the perpendicular line is the farthest left yellow line and the lowest node that is on the left in image 1 is on the right in image 2.