Filled water or powder snow cauldron extinguishes burning arrows that hit either side of the cauldron

Filled cauldron extinguishes burning arrows that hit either side of the cauldron.

What I expected to happen was...:
A burning arrow stuck in the cauldron.

What actually happened was...:
An ordinary arrow appeared, and one layer of water was removed from the cauldron.

Steps to Reproduce:

• Put the cauldron and fill it with water or powder snow.

  /setblock ~1 ~ ~ water_cauldron
  

• Shoot the cauldron from below with enchanted bow with "Flame".

Note: After 17w47a, the arrows that hit the cauldron's top are now extinguished, but they are still extinguished if they hit the sides of the cauldron.