Experience Bar Disappears

When you travel to other dimension, or die with Keepinventory your xp doesnt show for a while, and you cant use it on anvil etc.

What I expected to happen was...:
I was just hoping to see saved xp, but after changing dimension your levels dont show.

What actually happened was...:
You cant see your xp

Steps to Reproduce:
1. teleport to nether or Use TP on your mate in other dimension.
2. it may not show - dont know if every time.