Placing Leaf Blocks aboves Y=250, sometimes, you'll receives damage for no reason, and if you eat, you'll clip throught any Leaf block you're standing on, making you fall. 

Also, Villagers can clip throught Leafs when they wake up in the morning, resulting in them escaping from the Trading halls. 

Proof:

SVID_20230520_093621_1.mp4

SVID_20230520_092727_1.mp4