Parse local data store doesn't work correctly

I have a user object which has an array with other Parse objects.

For example: [PFUser currentUser] has an array of DeviceData, when accessing [PFUser currentUser] the array looks like this:

<PFUser: 0x170185d70, objectId: Sxf4A0FQNc, localId: (null)> {
    devicesArray =     (
        "<DeviceData: 0x170129a60, objectId: new, localId: local_95260d1c5bcdbf9a> {\n}"
    );
    email = "xxx";
    isDeletingEventually = 0;
    localityData = "<LocalityData: 0x170129ba0, objectId: LX0nYOE679>";
    username = "xxx";
}

when trying to access one of the properties (the model property) in the DeviceData object like this

[[[PFUser currentUser] objectForKey:@"devicesArray"][0] objectForKey:@"model"] I get the following error

error: Execution was interrupted, reason: internal ObjC exception breakpoint(-3)..

The process has been returned to the state before expression evaluation.

I can't access the objects in the array although in the documantion it is clearly written you should be able to access all of the objects in [PFUser currentUser]