This is one of those bugs that have been in the game for multiple years, but never addressed since there was no apparent bug tracker for this one.

Steps To Reproduce:

1. Have a testing area for mobs to pathfind through
2. Place down coral decorations on the floor, either normal coral decorations or fans
3. Spawn a mob, preferably hostile ones, and make them pathfind to you in some shape or form
4. Once they start interacting with those decorations, they will start jumping in place for a while, eventually they will pathfind to you but it varies depending on the target and if you move them while they are on top of the decoration.

A video will be provided to demonstrate the bug at large.