This was discovered by doing J1 demo. For some reason SequentialTransition of FadeTransitions stops working when invoked too many times with visibility of the node altered.

Run the attached code and press "Test" button.
If you get label text updated with the number and have "Finished" printed in the output, you didn't reproduce the issue.
Try pressing the "Test" button again.
At some point it stops running and you won't see any more "Finished" messages printed to the output.