2 Mobs Spawning instead of one. (The sign is correct)

[gamingjuts]

Description
While playing on my server i have been using the plugin and it has done perfect, until now. For some readon it just randomly wanted to mess up and spawn 2 mobs on the sign that is set instead of spawning one. It did this once before a long time ago. So i had to shut my dungeons down. I am just not sure on how to fix it when i have it all set up correctly. BTW i do have Towny on the server, but i am just not sure on how to be able to use dungeons if towny is the main part of the server. i need suggestions. I tried perworldplugins but it just messed everything up
//: # (A clear and concise description of what the bug is.)

Reproduce

Expected behavior
Only spawn one mob
//: # (A clear and concise description of what you expected to happen.)
When i jooin the dungeon and hit the distance trigger, i expected one boss to be spawned, however a bug happened and it spawned 2
the sign is like this
[mob]
Pirate
3,1,MM
d 5
Screenshots / GIFs / videos

Relevant configuration files

DungeonsXL.zip

[gamingjuts]

if you would like to join the server to see the bug for yourself (its not completely public, its in alpha) but you can do /warp dungeons and try it out, it is just weird. The first dungeon is a test.
173.236.104.37:25590 let me know if i need to op you.

[gamingjuts]

Here is the actual file, it didnt upload all the way, it was too big.
https://www.dropbox.com/s/5ssjw8pyqtb3naw/DungeonsXL.zip?dl=0

[Sataniel98]

Most likely a duplicate of #475. Signs must be broken, editing through a plugin that modifies signs e.g. on right click does not remove the underlying action point and you end up with two dungeon signs at the same location.