Game Version number: 1.3.0.144 (Steam)
Modded?: No

Issue Description:
Editing existing prefab compositions (anything from the Compositions tab, this doesn't seem to affect custom layer compositions), either intentionally or by accident, causes the composition to continuously duplicate its entities on every load. This will also cause your system budget to balloon out of control with extra arsenal entities, spawn points, etc. making it unable to update the save due to the excess entity duplicates. I believe I first caused this by dragging an entity on top of an existing composition (before I knew how to use layers) and before I knew it, I couldn't save my game anymore and wound up deleting my saves because I thought they were corrupted.