Paths keyframes in Ae only have speed graph and not value graph So no bezier handles unfortunatly. This has Always been this way.
I'm confused. You say "rotation" but you didn't include the property you are looking at in the graph editor and it shows bezier handles. You are also not showing a reference graph. What exactly are you trying to animate on this shape layer?
It appears that the mask path is highlighted so this is my guess to which property Op wants to animate. It is also my assumption that "rotation" means the nature of adjusting bezier handles for value graph Which are not available for path keyframes.