Harmony's Morphing tool controls your morphing sequence, this works by placing different types of hints to help the system morph the animation the way that you want it.
Hints are points that are placed in both the source and destination drawings. They associate zones and lines between the two drawings. Hints are used to fix problem zones, such as a line that is not following the colour fill zone.
Corners and points are more challenging, in general. Animation curves are complex and may be unable to match corners. It will generally associate a corner with its nearest neighbour; this is not always correct and it is why we use hint points to determine what goes with what.