Having this issue too, Rotation and Stride warping nodes dissapear after project restart or build, nodes cant be added by right clicking even with plugin enabled, nothing is found, but works by copy pasting from other project (like Lyra) and then they can be added by right click, all until next restart/rebuild when they disappear again.
Worked fine when my project was just blueprints (based on third person template), started happening after i added C++ and did my first build on the project.