The Bug:

Goats do not see trapdoors as an obstacle when attempting to ram an entity.

Steps to Reproduce:

• Place a line of trapdoors down.
• Spawn a goat on one particular side of the trapdoors. (See setup.png)
• Stand on the other side of the trapdoors and wait for the goat to ram you, or you can use the following command to make it ram you:

/execute as @e[type=minecraft:goat,limit=1,sort=nearest] run data modify entity @s Brain.memories."minecraft:ram_cooldown_ticks".value set value 1

→  Notice how goats do not see trapdoors as an obstacle when attempting to ram an entity.

Information:

In my testing, this only seems to work when standing on one particular side of the trapdoors.