When using the functions of the new Friends List, i witnessed that setting up your world for Multiplayer to make friends that are online join, LAN players can also join, even if they are not on your Friends List and received no invitation.
LAN Players can see your world automatically under the Multiplayer Tab and can join.
Setting up your world for your friends sounds like JUST players on your Friends List that you invite, can join and play with you.
Thank you for your report!
We're tracking this issue in MC-308102, so this ticket is being resolved and linked as a duplicate.
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