Short form: what might lead $_SESSION content to change between several PHP pages?
1 - In a php page, I add values to $_SESSION, then session_write_close() [note: values were successfully written in $_SESSION in a previous PHP page] ; if later in php script displaying $_SESSION, its contents displays as expected. This, I did believe, proves that $_SESSION content has been recorded correctly, without waiting the end of running the php script.
2 - In the next php page... $_SESSION displays without my last changes
Any idea? In which situations do you think this might happen?