Mob pathfinding ranges vary wildly. A Crossbow-wielding Pillager is able to pathfind through a massive range (going over a bridge and up a 20-block staircase to attempt to attack Villagers) while Zombies cannot pathfind unless placed on the staircase and Vindicators must be placed more than halfway up the staircase. When zombies and Vindicators were outside of this range, they would focus on minimizing the distance between them and the Villagers without realizing that a path was available.

Regarding the image showing enemies - the topmost layer of Grass is where Raiding Vindicators need to reach in order to pathfind to the Village above. The Zombie on the pillar of grass represents the minimum distance for a Zombie to begin pathfinding properly - it will also pathfind properly if placed at the bottom of the staircase. Raiding Pillagers pathed properly all the way from their spawn, but manually spawned Pillagers that do not join a Raid do not acquire the Villagers as a target without line of sight.

If I had to guess the limitation for Vindicators is a 16-block sphere with Zombies getting around 24 and Pillagers getting vastly more.

I would test further but I seem to have run into a separate bug involving a village's Raids breaking completely.