Hi Elyse,
Based on the error, there seems to either be an incompatibility of the saved JSON on the view that the user is leveraging or an issue around the timing of events on when the JavaScript and table is being loaded.
Given that this is only happening for a particular user and everything is functioning appropriately in your tests, the JSON incompatibility sounds more likely.
In the case where the users are able to save their views, if any of the values have changed on a particular column, there may be a chance of facing errors like the error shared.
A few things to check:
1) The JSON saved for that particular view for the user at hand. Check to see if any of the column values are different than what you'd expect based on your tests and values defined for the columns in Service Studio.
2) The defined attribute name and value in Service Studio for the 'Created By' column. Ensure that the definition is consistent with the rest of the columns.
Once you are able to check these, send a follow up note on your findings and hopefully it will get us a step closer to fixing the issue.
Thanks,
Justin