When a baby horse grows up, it keeps a baby horse hitbox. Meaning that those horses can go in 1 block wide tunnels, when normally they shouldn’t be able to do that. I tried recreating this bug on another computer and my smartphone and I got the same results.
To reproduce this bug you just have to:
Grow a baby horse
Save and exit
Re-enter your world again
Try riding it through a gap accessible for a baby horse and not for an adult one
I’m attaching a video proof of this bug.
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