illager patrols spawning even when the village inhabitance is all dead

illager patrols spawning even when the village inhabitance is all dead.

how to reproduce:

1. find a village (my one was a custom village)
2. kill all villagers in a village with /kill @e[type=villager] 
3. wait for a patrol  

 

(this screenshot is from 1.14.2 as you can see by the vindicators, but it has happened on 1.14.3 pre 1 and 2 as well)