AFK players have an odd look for their player name. Nothing appears in the console, but here's my config in case it's a config issue and a screen shot of it in action.

Config: http://pastebin.com/4Kepz9ja

What version are you running? Are there any symbols in the username?

2.0.1-b446 is what I get when I run /ess reload

The username is nothing special. It does it with all players who go AFK. But for reference, it's Teethdude.

Could you try updating your version of EssentialsX? Also, what server software are you using?

Try surrounding the value of afk-list-name in quotes (afk-list-name: "{USERNAME}").

Surrounding it in quotes worked. For whatever reason they either weren't there by default or I deleted them. Thanks for your help.

Redownloaded the EssentialsX jar, and it's still like above. Using Spigot. I'm two builds behind.
I even tried adding EssentialsXChat, but it didn't fix it either.

Spigot Version: This server is running CraftBukkit version git-Spigot-7d78b81-a867313 (MC: 1.11.2) (Implementing API version 1.11.2-R0.1-SNAPSHOT)