It looks like there is an incompatibility with the page Transition stack and the collapsible section button in the Display stack.
Dunno if this is a fixable ‘bug’ or an unfortunate incompatibility with the two animations. It seems like it is trying to ‘animate out’ when you click the expand button.
FWIW, here’s a bare-bones project I used to isolate the problem stack.
transition.rw8.zip (453.0 KB)