I hereby can just re-confirm that Hearthlings can and will get stuck in chairs! [Dev 2513]
on my RAM stress test savegame I never placed any chairs and I went for 30 days and 27 Hearthlings without any single one of them ever getting stuck/frozen (and I stressed the game engine a lot )
but the second I placed some chairs they got stuck in them like flys in electric fly traps
either from leaving the chair after eating on it or just by walking by when another Hearthling placed a chair right on their foot getting them stuck in place
although undeploying the chairs freed the Derplings but meh… still no comfy eating for them 