Hi,
thanks for opening the issue!
I commented there, but for the record:
Moodle doesn't implement right now a solid solution for doing SSO (from the Mobile app), this means that the app will not be able to do SSO until this is solved in Moodle.
Hopefully, MoodleNetwork will be replaced by SAML and we we'd be able to add support to it, but I cannot guarantee dates, etc..
Cheers, Juan