Interactive Grid value is not saving in table

In oracle apex(Interactive Grid) Table 1 value is fetched and inserted into table 2 in before header process. Table 2 is used to show values in grid . grid values should be saved in table 3. The grid value is saving in table 3 fine. but when updating the table 2 after insert process in before header process, it shows values in grid but does not save the grid value to table 3. this happens only when after updating the second table .