Resolution: Works As Intended
Affects Version/s: 1.16.1, 20w27a
Fix Version/s: None
Most likely intended and most likely a duplicate of
Illagers with banners, commonly known as "raid captains" or "patrol captains/leaders" can be spawned by a spawn egg of an illager type. It also works with the /summon, making the unused illusioners spawn as a captain/leader as well.
- Spawn a pillager using its spawn egg or use the summon command
→ Some of them may spawn with a banner
Only vindicators, evokers and pillagers and illusioners are affected.