I have noticed that some of my devices (smartphones) show max of 1080 and others (laptop, desktop, tablet) show the max at 4k for the same video.
Have you seen it throttle on different devices? What how you are receiving for data wifi vs. 4G cell?
I use 2.7k and it sometimes takes a bit of time to get up to full resolution. I tend to schedule my uploads though so they have time to reach 2.7k normally before they go live. I don't know the software you are using but is it definitely at 2.7k (2704x1520)?