Dying zombie converts to alive drowned

The bug

Zombies that die right before converting into a drowned, convert to an alive drowned. It should not convert anymore as the zombie is dead.

How to reproduce

1. Spawn 3 zombies into water.
2. Get a diamond sword with sharpness V, and hit all 3 zombies once.

   /give @a diamond_sword
   /enchant @a sharpness 5
   

3. Wait for them to start shaking.
4. Now, wait around 11~ seconds, so right before they convert you kill them.
   → The death zombie still converts into an alive drowned

Note: Step 4 might take a few tries to get the timing right.