Pathfinding issue: rather than cross a river, mobs drowned themselves in a hole.

Neither plugin or the launcher has anything to do with Mob AI / pathfinding so I think this is reproducible. -5325049790448493664 -556 63 -887

I attempted to escort a herd of cows across the river at the coordinates. Rather than follow me, they deviated course by 90 degrees and jumped down a hole with flowing water. They became lost (to me) or drowned. I thought it was extremely odd AI behavior.