I would be willing to bet they're not the exact same panel, and if they are, something with the fused display is causing these panels to have some less-than-stellar problems.
And fyi, I noticed the orange/yellow color-cast (especially on whites) at off angles on my retina-display MacBook Pro 13". I seriously think these IPS panels have been downgraded somewhere, intentionally or otherwise.
When i said im not 100% sure i really meant to say im almost certain they are the same panel 😉 The yellow tint issue has been present in all the LED and even the LCD iMacs, some some units didn't have it and others did, you have a bad unit as my 27" is perfect and has NO Yellow tinting whatsoever.