In company managed project, running this automation to sum all story points in an epic/parent to show the total on the epic/parent. Getting this error. 
It runs pretty consistently but getting this error on some.

Not sure what it means or if there's some field missing or what. Would think if it's missing a field everything in that project would fail but it doesn't. Right now I only have one project that fails every time. Oh and when the rule fails, it changes the story points field value in the epic/parent to "None" even if there was previously a number value in it.