I read on another site that shall not be named that Liberty Tree Tavern has removed the pot roast and several sandwich entree options for lunch and instead has moved to the same family style buffet you get at dinner.
Official menu on WDW site shows the "all you care to eat" listed for lunch but also a handful of À la Carte items - but NOT the pot roast:
https://disneyworld.disney.go.com/dining/magic-kingdom/liberty-tree-tavern/menus/
I am not at the park but there were photos of the new menu posted elsewhere on the web. Perhaps someone in-park can confirm with more information.
Official menu on WDW site shows the "all you care to eat" listed for lunch but also a handful of À la Carte items - but NOT the pot roast:
https://disneyworld.disney.go.com/dining/magic-kingdom/liberty-tree-tavern/menus/
I am not at the park but there were photos of the new menu posted elsewhere on the web. Perhaps someone in-park can confirm with more information.