Transition method buggy? Different sizes of circles in plot

I noticed a weird behaviour in my notebook. I am generating some data and plot them by creating circle svg objects, but the circles turn out to be of different sizes. The reason for that appears to be the transition method. It seems that for transition durations higher than around 100 miliseconds, the circles do not finish their transition to full size and stop growing, ending up slightly all slightly differently. For very short transitions this does not happen.


Is this a bug or expected behaviour?

You can have a look in my notebook, see the updateCircles function: