The Bug:

Mobs will attempt to pathfind over tilted big dripleaves.

Steps to Reproduce:

• Build the setup shown in the attachment below. setup.png
• Spawn a pig on the diamond block.
• Stand on the two big dripleaves so that they tilt.
• Hold the beetroot in your hand so that the pig will follow you.
• →  Notice how mobs will attempt to pathfind over tilted big dripleaves, which can lead to them falling, taking damage, and dying.