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I tested right here on Essentials v17.2 with all Rotom forms and there no bug. I had no idea what script you have changed. Even when I removed Rotom cry file, the game doesn't crashed.
You failed to mention that you are using Custom Scripts like Autosave. Delete them to look if this solves your problem (It is enough to put an =begin and an =end at the very beginning/end to the custom script).