This event occurs for grids with the PAGED style. It indicates that the user has clicked on the Next Page button. If you do not define a specific action when this event occurs, the grid implements the logic itself by generating a page-worth of MSG-PAGED-NEXT events. This is done with the MASS-UPDATE internally set to a non-zero value.
If you want to supply the logic by adding code to handle this event, set EVENT-ACTION to EVENT-ACTION-COMPLETE. This action-status informs the grid that it should not generate the MSG-PAGED-NEXT events because the Next Page has already been handled.