Saving simulation data at the end of the process like this means you only save the data if every step of kmc_analyze goes off without a hitch.

https://github.com/cmelab/morphct/blob/9fecea55bde8f78b9e564f6bec46276f8da6f42d/morphct/kmc_analyze.py#L2168

For example, we had a hard time locating the actual mobility/mobility error for a simulation because kmc_analyze didn't complete, despite the fact that the preponderance of the workflow was completed, including the kmc itself. I think maybe one of the plots failed.