Level can't save with Actor Sequence in it?

I tried to use the Actor Sequencer to make some platforms move a little less stiffly and it turned out great but when I try to save the level with them in it I get the following error:

Can’t save ‘WaterFarm_Auto1.umap’: Illegal reference to private object: ‘MovieSceneBuiltInEasingFunction /Game/Blueprints/SequencePiston.SequencePiston_C:ReTract_GEN_VARIABLE.Sequence.MovieScene.MovieScene3DTransformTrack_6.MovieScene3DTransformSection_0.EaseInFunction’ referenced because it is an archetype object.

It was only after this that I saw that this plugin has been 0.1 for apparently 2 years? Is this just a non-functioning plugin and I should look for another solution?

Upon cutting the problem sequence and pasting it back in, the level seems to have no trouble saving.