d3 transition effect position of svg line with bundle interpolation

Question

I use the following code to draw bended lines:

var line = d3.svg.line()
    .interpolate("bundle")
    .tension(0.8)
    .x(function(d) { 
    return d.x; })
    .y(function(d) { 
    return d.y; });

.....

links.transition().duration(2000)
        .attr("d", line);

(links containts path elements)

But if I changed the positions of the line, instead of smoothly moving to the new positions, the lines just jump immediately to the new position.

The "d" XML code that defines the appearance of the paths is very complicated, since it gets generated by the bundle interpolation.

Therefore I suspect that d3 is not able to calculate the transition on its own and I wanted to know if there are know solutions to this problem?