So for the first time I decided to wander around a new world in the most recent Snapshot 19w04b, looking forward to test the Performance and after a brief moment I found a Pillager Outpost, then I killed their Captain and decided to go to a Village to see how a Raid develops, all the Illagers managed to kill every Villager, followed by that the Raid finished and the Leader decided to head towards another Village so the small group of Illagers moved very fast, from there I decided to follow them until for my surprise I found a naturally generated Patrol, even with an Illager Beast.
But I was confused when I observed both Leaders were stuck in a specific spot, not moving a little bit, the rest of the Patrol was only moving in a little area, close to the Leader but just wandering around very fast, I decided to break some Blocks around the Leaders thinking they were stuck but still not even moving a little bit, I pushed them but nothing, so for the final Test I went in Survival Mode and I got closer to them trying to activate their AI or something, from there I discovered something wasn't working right with the AI since I was there close to one Leader which was a Vindicator, he only raised his Arm with the Axe but didn't move to approach me and I even got very, very close to him basically expecting a hit, but nothing, from there the next thing I did was get close to the Pillagers and the same behavior, they still were running but not even charging their Crossbows, just looking at me like nothing until I got close to the Beast which killed me without any problem, from there I just assumed there was a Bug affecting both Pillagers and Vindicators from a Patrol.