Witches disappear from raid mobs during wave 4 and 6

Witches will disappear from the raid mobs of wave 4 and 6

 

Steps to reproduce :

1. give yourself the bad omen effect and locate a nearby village
2. kill all raid mobs until you reach either wave 4 or 6
3. observe the amount supposed raiders

 

Expected results :

wave 4 (or 6) should at least spawn 3 (or 2) witches

 

Observation (Own) :

 

3 pillagers only spawn during wave 4