I would create a group called FalseDrop.
on drag and drop drop is not overlapping - set group FalseDrop to activated
and in the group:
arrow is not overlapping purple
-arrow set x : lerp(arrow.x,purple.x,0.5*dt)
-arrow set y : lerp(arrow.y,purple.y,0.5*dt)
arrow is overlapping purple set group FalseDrop deactivated
ofcourse you'd have to play with the value of 0.5*dt to find out which speed you'd like.