Transitions (specifically Translate/Rotate/Scale/Fade) do not play more than once when nested within multiple-levels of SequentialTransitions. The attached test case demonstrates the problem - the animation only runs correctly the first time.

Nested SequentialTransitions are likely to be used by developers stringing together moderately complex animations (and of course the animations will be expected to work more than the first time). For instance, I had to work around this bug in the demo I wrote for JavaOne.