There are three pillagers standing in water, 4/5 blocks away from land. They spin endlessly. Once I get close enough they stop and look at me. Then if I get closer still, they spin back and forth randomly. If I then get in the water near them they start looking at me and then shooting arrows at me when I get to close. At no point do they try to move towards me. If I move away from them then they continue spinning. They've been there for at least five in-game days.

Before they went into the water they continually walked around a small area 5-10 blocks away from the farm outside my house. One of the included images below shows where they were (the crosshairs point to where they were) in relation to my farm fence before they went into the water.