The problem is that both Subplots and Goals use a flag as an icon. One is square, one triangular... but they're both still flags, and flying in the same direction.

Something a bit more clear would be nice, even if you just reversed the direction of the flag.

Personally, I would make the "challenge bullseye" icon for goals, and change challenges to using an octogon (stop sign) instead.

Goal = target = bullseye

Obstacle = octagon = Stop