Hi,
Under APEX 26.1, I have an IG on a form p.18 of app 112. After adding a rows, when I Save the grid, the newly inserted line disappear. When I come back to the form, the line, the line appears. I checked that the new line is insterd into the table, it is. This alos happens to another grid in another form.
Newly added row before Saving:

After Saving (with a successful message), the line disapear:

Furthermore, when I delete a line, it disappear from the IG but when I come back to the form, it appears again. It seems deleting a line do not really delete the line.

Coming back to the form, the line still appears:

The process do exists:

Best regards.