GLKTextureLoader completion handler EXEC_BAD_ACCESS issue

Question

I am able to load a texture using the GLKTextureLoader however when i try to do it on a separate thread i get an EXEC_BAD_ACCESS issue.

working code.

NSError *error;
GLuint textureName = self.textureImageInfo.name;
glDeleteTextures(GL_TEXTURE_2D, &textureName);
self.textureImageInfo = 
[GLKTextureLoader textureWithCGImage:imageRef options:nil error:&error];
if( error )
{
    NSLog(@"Image loading error. %@", error );
}

Failing code.

self.textureLoader = 
[[GLKTextureLoader alloc] initWithSharegroup:_context.sharegroup];
[self.textureLoader textureWithCGImage:imageRef options:nil queue:dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0) completionHandler:^( GLKTextureInfo *textureInfo, NSError *error)
 {
     if( error )
     {
         NSLog(@"Image loading error. %@", error );
         return;
     }
 }];

Additional info. On the Thread that the completionBlock is running is where i get the EXEC_BAD_ACCESS with the following

Has anyone managed to get this to work?