Session data removed or overwritten

Additional information:
I halted the program in the controller where I set the userdata and the flashdata
I print_r the session and it shows both the flash data and the longer term userdata item + the Ion Auth identity data
But when I select * from ci_sessions only the Ion Auth identity data is there.

When does codeigniter save session data to the ci_sessions table? I would expect the userdata to be there, even if the flashdata gets removed.