Block hitboxs broken

Hi,

I am creating a mod with Mcreator 2021.1 on MC 1.12.2 (with the plugin). When I added a new campfire, I put a custom hitbox (0,0,0 and 1, 0.437, 1) and in game, the hitbox was weird: sometimes, normal but sometimes like if it was 0,0,0 and 16, 0.437, 1 or 0,0,0 and 16, 0.437, 16 (screen). Can someone help me?

PS: I am french, sorry for the english!