Article written by Austin C.
When playing back a UMG animation with a keyframe at the very end, the animation may not play to completion, leaving parameters at unexpected values. For example, animating opacity from 1 to…
https://dev.epicgames.com/community/learning/knowledge-base/ZGa7/unreal-engine-last-frame-of-umg-animation-skipped
One trick is to trigger an event once the animation is complete and set the final state of any animated component. It requires more effort, but it will guarantee that the items remain in an intended state.