Soooo only certain AT&T customers are getting Pie /One UI on their Note 9?

Actually on my unlocked note whenever I pop in a different carrier sim it runs their graphic when you turn on the device.

It shouldn't
I'm on the unlocked firmware right now
When restart it shows Samsung logo then enter passcode I use both my tmobile and Att
 
I did change the animation settings on dev options, I'll give that a try shen I get home. Thanks for the tip
 
Curious, you didn't by any chance enable "Reduce Animations" in Advances Settings, did you? That has caused odd display issues for some. But to answer your question - no, our screens are not doing that.

I did change the settings in dev options for animations. I'll try and change then when I get home. Thanks for the info.