CIG Realm ID Configuration for Parent and Child Site

I have tried to set up 2 Procurement projects in CIG, one to point to Ariba Procurement parent and one to Procurement Child.

In the Realm ID tab of the project, the selection automatically changes to the latest realm saved in either project. I have tried to select the Parent realm for the Parent project, save it and then change the realm in the Child project, however the selection does not stay saved.

Is this a bug in the tool or can only 1 Procurement project be configured at a time?

Thanks.