The particular defect you listed has had a fix made available for it since 13.2.0.3 and higher (including higher versions not just patches, so 13.3 and 14.2 are also included).
Are you using the OnDemand Portal or are you using your own SSO solution (i.e. a federated SSO configuration)?
If the former, then provided you are not on a lower version than I mentioned above, then you should try logging in using the following values in the app, provided you have also granted the appropriate permissions in Clarity for using the app:
URL: OD Portal URL
User Name: OD Portal User Name
Password: OD Portal Password
To be clear, the Clarity Mobile Timesheet App is itself not an SSO enabled application - you have to provide credentials to it and login - but it can work on SSO enabled environments if those details are given, as Clarity would then take those credentials and authenticate the user against the same LDAP (directory server of users) that the OnDemand Portal also uses to authenticate.
However if you are using a federated SSO configuration, i.e. you have your own branded SSO login page for Clarity as well as your other apps, it is not as straightforward (maybe not even possible), as your own authentication credentials would not be matched to the LDAP server that Clarity is connected to.