Confirmed on 1.21.7x for XBOX Series X, Windows, and Android (I don’t have any other versions with which to test)
Possibly started when the new UI for Worlds/Realms/Servers was introduced
I am only able to see one LAN server at any given time
I host three, a Survival, Creative, and Flat for my children & I
Each Server is a unique Ubuntu server, with a unique IP address
Each Server uses the standard port configuration (since Xbox can only see 19132)
Each server is running the correct version
Which server is displayed at any given time seems completely arbitrary
Navigating through the menus, or joining a local game or realm and returning to the “Worlds” section often results in a different server being presented.
I do have “LAN Worlds are shown” enabled
Toggling that on/off doesn’t restore all servers to visibility
Occasionally all LAN worlds disappear
I AM able to add the servers manually in the Servers tab on PC, but Xbox doesn’t support this.
Plus, they should all be visible int he Worlds section as they always have been
This issue is being tracked at MCPE-190764. Also, you currently have your email address as your username. If that is not intentional, please change it here:
https://report.bugs.mojang.com/servicedesk/customer/user/profile