A script of mine keeps losing a cached reference to SkeletonAnimation. So I ended up adding a gameobject.getcomponent in Start() to set it again and then execute the following logic only after this step is done. It worked after that. However, I would get the same issue if I remove the cached reference and only leave the gameobject.getcomponent setter. So I need both for it to work as intended. I did not experience the same issue with 3.7 runtimes.
Unity 2019.1.9f1, latest 3.8 runtimes