Bukkit

Once you go far enough from range, guards vanish and don't reappear. Only way to make them reappear is to reload the server. Guards also don't show up upon initial joining of the server.

I have the same. But guards do not appear even after the server is rebooted.

I mean when the plugins are reloaded. i.e. when you use "reload" on the terminal or "/reload" in game.

Thats because we are hiding their names from the player-list.

I will try to fix it tomorrow.

Should be fixed in 3.2.8

I have updated the plugin and it looks like it was partially fixed. Upon joining the server, all Guards spawn as they should. When walking out of render range (guards de-render as normal), and when I walk back into range they don't reappear. They do re-apper when I drop out out of the sky however. 
I like your work so far. It's no easy task developing plugins and fixing issues.

Problem is that I cannot register when the guard is despawning.

So the fix right now is to register, when a player moves far away

from the guard and when he returns afterwards the guard actually will be respawned.

Can you somehow measure the distance between you and the guard when he despawns and when he should reappear but doesnt?

I can get to 51 blocks away from the guards before they despawn. It should be the same distance that they reapper.

If I go up to cloud level and drop down, they reappear. 

Hope this helps.