When you move vertices, the tangent handles of the two adjacent vertices remain fixed in their current position. You can make them automatically adjust to create smooth curves between the vertices by pressing the G hot key as you move vertices.
You can reverse the behaviour so that dragging vertices automatically adjusts tangents without using the hot key. You reverse the behaviour by setting the following environment variable:
To reverse functionality of the G hot key:
When you click or move a vertex on a garbage mask, the tangents are automatically repositioned. When you press and click or move a vertex, the tangents are not repositioned.