Here is the scenario of steps to reproduce the problem.
- Create a new table with at least one column with a String data type.
- Add row data to include data that will fit within the string column (500 or less characters)
- Add row data to include data that will not fit within the string column (501 or greater characters)
- Change the Column data type from String to Text
- Add row data to include data that will fit within the Text column (501 or greater characters)
The error when adding a row is: Internal Server error: <GUID>
If you immediately change the data type to Text before adding any row data, the addition of row data always works.