Table and matrix reports will automatically hide rows with repeating values for readability. However, the underlying data is still present and can be viewed by hovering over the cell. The data is available in exports but will have the same font colour as the background cell.
You can override this behaviour by adding a custom ‘Sort by’ selection that is not on the first column.
You can also re-add the first column as a hidden field and enable sorting on this to keep the default sorting and override the hidden cell value behaviour.
This behaviour can only be overridden in Table reports and not Matrix reports