I noticed that animations works if you have at least one other visible module inside the region.
I think the problem is in the function updateWrapperState (main.js) that will change the region wrapper’s style to “none” if no module inside the same region has a style.position of “fixed”.
I’ve just added a PR that hopefully fixes this issue: https://github.com/MichMich/MagicMirror/pull/744