There was an issue handling session timeout in the Kapsel container Fiori Client is built on. I can't recall the details, but I believe the solution is will be addressed in a soon released version of SMP SDK 3.0 SP10. Not PL02, but a later one.
If you are using the app store version of Fiori Client, you can try 1.5, but I do not believe that has it. I don't think 1.5 is on the iTunes app store yet, but should be soon. Windows and Android has it.
Regards,
Kevin