If user use inter-dimensional tp, user level disappears.
As far as I know, it happens when tp to other users.
In a word
Teleporting with coordinates doesn't know if that happens.
and this isn't serious, but it makes the user pay attention.
Currently, the way for users to fix this is to go out and come back to the game.
or
When you eat experience points, you can see the level you couldn't see.
Please fix it asap