Some weird stuff is happening with Pillager spawning, some of which may or may not be intended:

1. Vindicators are spawning alongside the regular pillagers.
2. Occasionally pillagers spawn invisible. This isn't because of small rendering distance because my rendering distance is set to 15 chunks and other entities display correctly. I can hear the pillagers but can't attack or see them, but I can see where they are shooting from, I can see the effects of them attacking, I can see the damage from the Illager Beast, and I can see villagers and other mobs around and even past their location. After I get killed and respawn the pillagers are usually visible.
3. Two or three pillager groups spawned during the first day in a world with a desert spawn and there were no villages anywhere nearby. (The only generated structure I could find was a shipwreck off the coast of the desert).
4. Pillager spawn rates seem high in general and sometimes multiple groups spawn during a single day. Since villagers don't fight back they are quickly annihilated.

Again, some of this behavior may be intended. Some documentation on what to expect as far as spawn rates, distances, etc. would be helpful to help give more accurate information about what is or isn't a bug.