Do I have defective 3g? iPhone6 iOS8.3

Hi,

I am wondering whether my 3G is defective because when I share a post (via apps that shares on Facebook such as Feedly, Pocket, etc.) while on 3G, the thumbnail is not loading nor attached to the shared post. While on WiFi it is working as intended. I have reported this to Facebook, but I have yet to receive any word from them. My assumption is that this is "optimization" on Facebook's, that if they detect your 3G to be slow/or working abnormally, they don't attach the thumbnail to the post, which is my main concern for defective 3G.

Unit is less than a week old. iPhone 6, 16gb iOS8.3

I asked a friend to test, and she is able to share a post with thumbnail even on a 3G connection. She is also on iOS 8.3 the only difference is that she's on iPhone5/5S. Thoughts?

Thanks.