Drowned mob freezing in place in 1.15

The Drowned mob has broken in the new 1.15 update. I have not tested with tridents yet. This may have been a one-time thing, I am not sure.

What I expected to happen was...:
The Drowned to attack me and kill me, like they normally do swimming towards me.

What actually happened was...:
They chased me for about 5 seconds then just stopped and stood there. They didn't go up or down.

Steps to Reproduce:
1. Find some natural Drowned in the ocean.
2. Go into survival mode.
3. And wait for the Drowned to stop.