iOS crash on Social Leaderboard LoadScores after upgrading to Unity5

Hello,

I have the following code that I use to setup leaderboards on my game:

 public void Setup(Dictionary<string, IUserProfile> friendsHashTable)
     {
         ILeaderboard leaderboard leaderboard = SocialManager.GetSocialPlatform().CreateLeaderboard();
         t$$anonymous$$s.friendsHashTable = null == friendsHashTable? t$$anonymous$$s.friendsHashTable : friendsHashTable;
         
         if(!IsCompleted())
         {
             return;
         }
 
         leaderboard.SetUserFilter(GetFriendsFilterList());
         leaderboard.LoadScores(OnScoresLoaded);
     }

It used to work fine on 4.6.4 and it works fine on Android as well for 5.3.4f1; however when I run it on iOS it crashes with the following error message:

 2016-03-29 18:34:46.506 bith[4820:60b] -[GKLeaderboard initWithPlayers:]: unrecognized selector sent to instance 0x16f63af0
 2016-03-29 18:34:46.726 bith[4820:60b] Uncaught exception: NSInvalidArgumentException: -[GKLeaderboard initWithPlayers:]: unrecognized selector sent to instance 0x16f63af0
 (
     0   CoreFoundation                      0x2f2a0ee3 <redacted> + 154
     1   libobjc.A.dylib                     0x39a3bce7 objc_exception_throw + 38
     2   CoreFoundation                      0x2f2a47f7 <redacted> + 202
     3   CoreFoundation                      0x2f2a30f7 <redacted> + 706
     4   CoreFoundation                      0x2f1f2058 _CF_forwarding_prep_0 + 24
     5   bith                                0x01770608 ___ZN10GameCenter13GcLeaderboard6CreateEP9MonoArray_block_invoke + 432
     6   GameCenterFoundation                0x2fe5aca1 <redacted> + 12
     7   libdispatch.dylib                   0x39f24d53 <redacted> + 10
     8   libdispatch.dylib                   0x39f24d3f <redacted> + 22
     9   libdispatch.dylib                   0x39f276c3 _dispatch_main_queue_callback_4CF + 278
     10  CoreFoundation                      0x2f26b641 <redacted> + 8
     11  CoreFoundation                      0x2f269f0d <redacted> + 1308
     12  CoreFoundation                      0x2f1d4729 CFRunLoopRunSpecific + 524
     13  CoreFoundation                      0x2f1d450b CFRunLoopRunInMode + 106
     14  Grap$$anonymous$$csServices                    0x341436d3 GSEventRunModal + 138
     15  UIKit                               0x31b35871 UIApplicationMain + 1136
     16  bith                                0x00023d94 main + 164
     17  libdyld.dylib                       0x39f39ab7 <redacted> + 2
 )

From testing the t$$anonymous$$s seems to be the call that causes the issue:

 leaderboard.LoadScores(OnScoresLoaded);

Has anyone come across t$$anonymous$$s before? Or does anyone know what may be causing it?

Thanks.