If you create a react grid without any GridColumn components and then add those components later, the added columns do not show and the grid is empty. It appears, after a quick look that the columns have a width of 0 pixels. They exist in the html, just not displayed.
See https://codesandbox.io/s/mmr894nllp as an example of the problem. This example starts with a populated grid. You can add columns and data using the buttons above the grid. This works fine. If you then "Reset" the grid with the button, which removes all data, any attempt to add columns and data will show a blank grid.