Width during transition of text only rotor

Issue Summary

Hi,
First of all, awesome module - thanks!

I've come across a strange & not entirely consistent UI error.
It seems that sometimes, in various versions of I.E. (mostly 9), the first rotor of text will resize during the transition. It looks fine both before and after the transition, but during the transition the width of the first item seems to increase (progressively) to the width of two items, resulting in the text of the first overlapping that of the second.

Attached is a screenshot of it, half way through the transition.
I'm using Drupal 6.22.

Does anyone have any ideas?

Thanks.