Non-source water blocks will flow through end rods.

Steps to Reproduce:

1. Place an end rod
2. Place water next to it

What I expected to happen:
Flowing water would treat end rods as an obstacle when flowing in its direction and redirect itself or stop itself if there was no other path to take.

What actually happened:
When a water source block is placed, flowing water blocks from it can go through end rods without the source waterlogging the end rod.