[Florian Mondl]

Path interpolations can not be done like this. You need to place your keyframes at a fixed time interval (for example one second) and then apply the linear function to the mask path like this:

 

var A = thisComp.layer(“layer”).transform.position[0];
t = linear(A, 0, 100, 0, 1); valueAtTime(t+thisLayer.inPoint);